Oftentimes we let people into our homes with very little thought that maybe the person we are opening our doors to could be hiding deadly intentions.

When Marti Hill had failed to show up for work in September 2010, panicked co-workers called police, and when authorities arrived, they weren't prepared for what they would find.

Marti Hill loved her job as a graphic artist for an apparel company in Overland Park, Kansas, and her co-workers loved her. The single mother of two rarely took a day off, and was never late getting to the office.

On the morning of September 8, 2010, Marti wasn't in the office by her usual 8 a.m. Then she missed a weekly operations meeting two hours later. Everyone took notice.

"We work so closely together that she would have told me she wasn't going to be there," said Marti Hill's former co-worker Stephanie Scheibler.

Marti hadn't told anyone she wouldn't be at work that day, and when they tried calling and texting, there was no answer.

Was there panic in the office?

"We all remained pretty calm but we thought that something needed to be done," said Scheibler.

So Marti's boss drives to her house in nearby Prairie Village. He immediately notices her SUV parked in the driveway, but no sign of Marti.

"He knocks on the door, no answer, kind of walked around the house, didn't see anything suspicious," said Scheibler.

When everyone at the office heard Marti's truck was there but no answer at the door, they immediately call police to conduct a welfare check at the house.

Co-worker: "Her daughter lives with her part-time, but she's in high school and we didn't want to call and alarm her."

The Kansas City neighborhood Marti called home was known for its quiet, safe streets.

"Get very few calls in that area," Prairie View Police Officer Bill Baldwin tells Crime Watch Daily. "The calls we do get typically are of property-crime type."

Around midday on a Wednesday, Officer Baldwin answered the call for a welfare check.

"I went to the front door and knocked. I didn't receive any kind of answer," said Officer Baldwin.

He walks around the outside of the house, looking through windows to see if anybody is home.

At what point do you make entry into the house?

"When I realized that the front door had been unlocked," said Baldwin.

Once inside, the officer immediately notices something suspicious.

"I first noticed that there was a woman's purse sitting on the kitchen dining room table," said Officer Baldwin. "I believe she's probably close at this point."

Officer Baldwin searches every room on the first level, then sees stairs leading to a basement. He makes his way down.

"It is very dark, and I've got a flashlight and I'm announcing my presence the entire time. I don't want to scare anybody that actually lives there," said Officer Baldwin.

Before reaching the bottom of the stairs, he notices blood on the floor. Then he spots someone lying nearby.

"I don't know this is Marti for sure at this point, but it appears to be a female subject, and she's laying in this giant pool of blood, facing away from the stairs in kind of a fetal position," said Officer Baldwin.

Officer Baldwin wasn't sure if she was dead or alive.

"I could not feel a pulse," said Baldwin.

But then she turns toward him, revealing her extensive injuries.

"Her face looked extremely swollen," said Officer Baldwin. "Her hair was just soaked in blood. I looked down a little further and then I saw the cutting on her throat."

Covered in blood from head to toe and unable to speak, Baldwin still wasn't certain this was Marti Hill. Paramedics arrive and rush the woman to the hospital.

Prairie Village Police Sergeant Luke Roth rode along in the ambulance.

"I'll be honest with you, she was covered in blood to the point I did not know what race she was," Sgt. Roth tells Crime Watch Daily. "I thought she was a black female until she got cleaned up for surgery, I mean that's how dried the blood was."

On the way to the hospital, Sgt. Roth hoped the critically injured Marti could provide some sort of clue to what happened.

"We were trying to get what you would call a 'dying declaration.' Some sort of statement as to who did this, and we were unable to ever get any response from her," said Sgt. Roth.

One of Marti's co-workers who had returned to the house delivered the terrible news to the office.

"The only thing she said to us was 'There's a lot of blood,' and that's all that she said," said Stephanie Scheibler. "It was terrifying, because we didn't know if she was dead or alive at that point."

When paramedics reached the hospital, doctors declared Marti Hill a Level 1 trauma patient.

"My mom had very deep lacerations on her throat," said Marti's daughter Mackenzie Hill. "She also had multiple skull fractures."

Her chances of surviving were not good. Detectives knew it was unlikely that Marti Hill would be able to help them find the person who'd beaten her, stabbed her and left her to die.

"They had a personal reason for the extent of injuries that she suffered," said Sgt. Roth.

But who would want to kill Marti Hill? And were they done trying?

For several tense days, it wasn't clear if Marti Hill would live or die. In those same days, it also wasn't clear just exactly who tried to kill her.

"It was the worst crime scene that I had ever been involved in," said Prairie Village Police Detective Jason Wakefield.

Marti's injuries were so extensive, her own family wasn't sure it was her.

"When I walked into the room I saw her in front of me, my first reaction was, kind of fell to the ground," said daughter Mackenzie Hill. "The only thing I could really recognize on her was her hands."

"There was like blood creeping out of one of her eyes, besides the swelling on her face, so it was really hard to watch," said Shirley Roth, Marti's mother.

Marti was unconscious, and detectives knew they'd have to find a suspect without any help from their victim. Sergeant Luke Roth and Detective Jason Wakefield were assigned as lead investigators on the case.

No sexual assault, no forced entry, no sign of a robbery. Who are you thinking could have done this to her?

"Initially it was the ex-husband, or a boyfriend that nobody knew about," said Roth.

Marti had been divorced from Steve Hill for seven years. But the two were in constant contact because they shared custody of daughter Mackenzie.

"She'd have Mackenzie on the weekends and I'd have her during the week. So I saw Marti pretty regular," Steve Hill tells Crime Watch Daily.

On the day of the attack, Steve had been trying to reach his daughter after school, but his calls were going unanswered.

"I was getting a little frustrated with her 'cause I kind of thought she was, you know, dodging her dad," Steve said.

It wasn't until late in the evening that he learned what had happened from Prairie Village Police. Cops called to say his ex-wife had been attacked, and that he was a person of interest.

"Being the ex-husband that I've watched enough television shows, I knew that they were coming to question me," said Steve Hill. "I didn't know the severity, I had no idea what had happened to her, other than she had been attacked in her home."

But Steve wasn't told how dire the situation actually was. When cops came knocking at his door, Steve was more than happy to cooperate.

"He did everything we asked. The best way to put it is, is he wanted to find out who did this just as much as we did," said Sgt. Roth.

Steve had a alibi for that morning. He told cops he'd brought his daughter to school, then went into work. Before leaving, officers got a DNA sample.

"They wanted to scrape underneath my fingernails and take hair-follicle samples and all that stuff," said Steve Hill, who allowed them.

But until the DNA results came back and his alibi could be confirmed, Steve wasn't even allowed to see his daughter.

"I couldn't get my daughter after school," said Steve. "They basically wanted to keep her away from me until they had eliminated me as a suspect."

To daughter Mackenzie, who was 15 years old at the time, it didn't make any sense.

"I knew that he would never do anything like this to her, so that was really hard for me to understand at the time," said Mackenzie.

But like police, Marti's son Stephen Kirby thought everyone in his mom's life should be considered a suspect -- even the man he once called stepdad.

"In my head he was a suspect, but he wasn't my number one," Kirby tells Crime Watch Daily. "I felt like we were after somebody else."

And the same question lingered: Who would want to kill Marti Hill? Her family, friends and co-workers, had no idea.

Did you know if she had any enemies?

"Oh, never," said co-worker Stephanie Scheibler. "I can't even imagine in a million years that someone would."

But later that night, after detectives left Steve Hill's house, a strange thought surfaced.

"I just remembered somebody told me that she had had somebody working on her house, so I tried to call one of the detectives," Steve said. "I ended up getting a voicemail on his cellphone and I just left him a message."

Marti's mom Shirley Roth had also told cops about the handyman. She's the one who recommended Brian Pennington to her daughter after he did work on her own home.

"It was stucco in the house and he was just fine," said Shirley Roth. "He did a really nice job. He became a friend of ours."

Shirley hoped maybe Brian Pennington had seen something suspicious while working at her daughter's home, something that could help with the investigation.

"So right away I looked at my phone and gave [Sgt. Roth] Brian's telephone number," Shirley said.

"Quite honestly we were looking to see if he might have seen anybody at the house that was staying with Marti, that she may have been dating, that she may have been in communication with, because we had nothing to go with," said Sgt. Roth.

Detective Jason Wakefield first reached Brian Pennington by phone. Pennington agreed to meet with him.

"He invited us to his house," said Wakefield.

Two days after the brutal attack left Marti Hill at death's door, Det. Wakefield and Sgt. Roth head to the home of her handyman. Their entire 90-minute conversation with the father of two was recorded.

Detective: "What did you think when you heard that Marti got attacked?"

Brian Pennington: "I really didn't know what to think. She's a really, really decent lady."

But even before going inside, a red truck in Pennington's driveway sparked suspicion.

Detective: "You ever drive that red one at all?"

Pennington: "No, it doesn't have plates on it, it just sits there."

The day of the attack, Marti Hill's neighbor told cops she'd seen a beat-up red truck on their street.

"She said she saw this truck around 8 o'clock in the morning and it was being driven by a white male of smaller stature," said Det. Wakefield.

Then another red flag: scratches on the handyman's face.

"He told me they were from a pit bull," said Wakefield. "When I looked at them, it didn't appear they were dog scratches, it appeared they were more fingernail-type scratches."

Detectives ask Pennington if he'd been back to Marti's house since finishing the work two weeks earlier. He claimed that would've been impossible.

Pennington: "I'm so far in debt right now I can't even afford to go to the gas station, really."

"The entire time he talked about his financial struggles, there was no way that he could have drove to Prairie Village, Kansas, an hour and a half away," said Sgt. Roth.

Pennington's wife Jessica corroborated his alibi.

"She said he was home all night with her," said Roth.

With so much blood in Marti's basement, detectives were sure any suspect would have blood evidence on their clothes.

Detective: "Hey Brian, do you, you don't have any clothes with any blood on them or anything like that, do you?"

Pennington: "No."

Detective: "No? Do you mind if I take a look real quick, is that all right with you?"

Pennington: "Yeah."

Pennington agrees to let detectives search through the laundry hamper.

"We had recovered a pair of jeans that had red stains that we could see on the hems and within the thigh portions," said Sgt. Roth.

But the handyman had an explanation. He claims it's grease, and denies it's blood.

By now, cops weren't buying it. Pennington had quickly become their prime suspect. But could they push him to confess?

Detective: "There's just so much evidence, I mean it's overwhelming. Somebody's going to get caught for this, there's no doubt in my mind, absolutely zero doubt. We just have to figure out why this happened. What do you want to tell us, Brian?"

Pennington: "I really don't know anything."

Before leaving, detectives ask if they can take his stained jeans. Pennington allows them.

"We were shocked," said Sgt. Luke Roth. "We went to this house with the thought process that Brian might lead us to whoever was responsible. We now left the house thinking there was a good chance Brian was responsible and that we might have a key piece of evidence that could solve that."

Investigators deliver the jeans to the Johnson County crime lab. That very night preliminary tests confirmed the stains are human blood. The next day, more confirmations: the blood matches Marti Hill.

Cops were close to making an arrest. But before they pounce, Marti Hill's family had some even bigger news to share.

"We got a phone call that Marti had started talking," said Sgt. Roth.

The first memory you have is waking up in the hospital and seeing your dad?

"Yes," Marti Hill tells Crime Watch Daily.

That was 12 days after the attack that happened just before she headed to work.

"I heard something and kind of looked out the front window," Marti said.

Brian Pennington was at the door, the handyman who'd completed work inside her home two weeks earlier.

"I think I was kind of wondering why he would be there in the area that early," said Marti.

That's because she knew Brian lived 90 minutes away in Leeton, Missouri.

"I'm thinking maybe he had another job in the area," said Marti.

Marti was considering selling her home at the time, and Brian Pennington said there was something in the basement he wanted to show her that needed to be fixed. So she invited him inside. Before they reached the basement, she noticed something was odd.

"I remember talking and I don't exactly know what I was saying or asking him, but I'm feeling like he's not answering, or he's not saying anything," said Marti.

You were walking down ahead of him?

"Yes, so I'm ahead of him and then two steps away from the stairs I kind of looked to see, you know, why he's not responding or saying anything," said Marti. "At the same time, he grabs my neck. I just remember him holding so very tight and when I tried to look, he was away from me, which all seemed so odd. And it was just getting tighter and I kept saying 'Why, what are you doing?' and 'I don't understand, what are you doing?'"

Marti felt her voice get weak just before she passed out.

"I then remember waking against something and my back is hurting. And I'm trying to get back up and get balanced and just still fighting and fighting and kicking and asking him to leave, and 'What are you doing?' and just so puzzled and still so confused, you know, it just, it was all happening so fast, but then after that I remember nothing," said Marti.

When he was done, Marti had several fractures to her skull and face and a severe brain concussion. She also had four quarter-inch-deep, six-inch-long stab wounds in the neck.

"The way that he cut her neck, had missed the carotid artery, and if he would have been just millimeters away she would have bled out," said Mackenzie Hill.

About four hours after the attack, Marti's boss was at her doorstep.

Could you hear anyone knocking on the door?

"No," said Marti.

When she wouldn't answer the door, her co-workers called police. Had her co-workers not followed their gut instinct and called police, Marti Hill likely wouldn't be here today.

"They saved her life," said Sgt. Luke Roth. "I don't think she had much more time to lay on that basement floor."

Do you think of them as your angels that day?

"I definitely, definitely do, I mean I definitely would have been there for them," said Marti. "I think that's important to make sure you're being respectful to your other co-workers, and I think that would be given back to you."

Three days after the attack, with her eyes still swollen shut, Marti started to speak. And the first thing she said was her attacker's name.

"I kind of understand that I was just doing whatever I could to get that out, I was mumbling it out," said Marti.

"I'm so proud that she could say that so soon," said Marti's son Stephen Kirby.

The same day cops also identified Brian Pennington as the suspect after blood found on his jeans matched Marti Hill's. It was information they didn't want anyone to know -- including her family.

"We did not want to cloud anybody's responses or feed anybody's information," said Sgt. Roth.

They also wanted to gather more evidence before taking Brian Pennington into custody, which happened two days later.

"We actually saw him driving down the highway," said Sgt. Roth. "Jessica was driving, he was seated in the passenger seat, and we actually did a car stop on the highway and took him into custody."

Was he surprised?

"No," said Roth.

Marti's family and the entire community were relieved -- especially her mother, who had Brian Pennington to Marti.

Doctors were now cautiously optimistic that Marti would pull through. But the road to recovery wouldn't be easy.

"We didn't really know the extent of the injuries," said Marti's daughter Mackenzie. "We didn't know exactly what was going to heal all the way, and you know, if she would ever be her normal self again."

In the beginning, even the most simple things were difficult for Marti to do.

"Her eyes were completely swollen shut, so in order for her to look at my brother and I, she would just hold her eye open," said Mackenzie.

Once the swelling went down, Marti still had trouble seeing.

"I specifically remember them asking me to walk down a line, and my response was 'Which line?' I was seeing two, and there was one," said Marti.

She also had to learn to walk again.

"Balance was a big issue for a long time," said Marti.

"I remember we would put a harness on her and I would hold the back of it while she would kind of balance back and forth and walk down the hallways," said Mackenzie.

Marti was hospitalized for nearly a month, and after her release, she required around-the-clock care.

"I know that I would have been there for them, but you never -- you don't always get that opportunity to see who's going to just really show up and be there," said Marti.

After years of rehabilitation, Marti hill still has trouble hearing out of one ear.

"It echoes when I talk," said Marti. "They actually said I would get used to that, but that has not happened."

She says getting back to the gym was a big part of her recovery.

"I lost a lot of strength, and just finally getting back to where I was working out, doing what I had done before just made a big difference," said Marti.

Marti would need her strength to face her attacker in court. Brain Pennington was ultimately charged with attempted first-degree murder and aggravated burglary. Prosecutors say he had a long rap sheet.

"He had 26 prior convictions," said Johnson County Assistant District Attorney Vanessa Riebli. "Those types of crimes were domestic violence, they were also crimes of dishonesty, burglaries and thefts. He just seemed to be a very short-tempered individual."

In addition to the jeans with Marti's blood on them, Pennington's cellphone also tied him to the attack.

"His wife texted him at I think it was approximately 7:59 a.m. to ask where he was located," said Riebli. "The cellphone information provided a tower location next to Marti's house."

The text also blew his alibi, proving that he wasn't home the morning of the attack like his wife Jessica first told cops.

"I think she gave that information to protect herself and her children," said Riebli. "He had been physically abusive to her."

Do you think she was afraid for her own safety?

"Absolutely," said Riebli. "When she found out what he had done to Marti was when she was done protecting him."

Brian Pennington eventually pleaded guilty and was sentenced to 28 years in prison.

You had to face your attacker in court. What was that like for you?

"Oh gosh. Mostly just the flooding of 'Why?'" said Marti. "And 'I just don't understand,' and 'You're not the person I thought you were.'"

Pennington never offered an apology nor an explanation for the attack.

"I probably will never know," said Marti. "There's not going to be a good answer."

Marti Hill is now focused on using her experience to help others. She talks to groups about how to stay safe and how to get through traumatic events. She also recently started writing a book.

"I feel like that is such a gap in my life, I think that by putting every detail down and walking through it, it becomes where I know it and I understand it," said Marti.

If there is one thing she could say to Brian Pennington, what would it be?

"I don't think I have anything to say to him," said Marti.

Is there any part of you that can ever forgive this man for what he took from you?

"I feel like it would only be hurting me to not forgive him. I think it wouldn't affect him, really," said Marti. "I think it makes my life different to be able to forgive and move on and be stronger."

It's hard to imagine Marti Hill becoming any stronger than she already is.

And Marti promises she will be at every parole hearing Brian Pennington will have during his 28-year prison sentence to make sure he can't do this to someone else.