A little boy's mother faces off with a true monster of a man. Crime Watch Daily has the details of what led up the explosive confrontation.

It was a case that captivated Los Angeles and beyond: a father takes his son to Disneyland -- then the little boy goes missing.

It is said there is no more crushing pain than that caused by the loss of a child. And if that child is savagely murdered, there's a rage that can ravage the soul. In the case of "Piqui" Andressian, even seasoned prosecutors and veteran cops braced themselves for the wretched reality of a murder they'll never erase from their minds.

Aramazd Andressian Jr., nicknamed "Piqui," wasn't just a precious child. Piqui was an old soul, a magnet for people and animals. He loved nature and planting gardens. He was the only child of Aramazd Andressian Senior and Ana Estevez.

Ana's journey to motherhood was hard-fought. She had been through in-vitro fertilization, spending thousand of dollars to get pregnant. She had had five miscarriages.

Not long after Piqui was born, the marriage between Ana and Aramazd soured. The couple divorced, and the court ordered joint custody. Under the terms of the visitation agreement, the couple was to exchange the child on neutral turf.

"There was always a mutual agreement to meet at either a police station or somewhere in public," said Los Angeles County Sheriff's Detective Louie Aguilera.

The divorce was a bitter one. Ana didn't trust Aramazd. She had dash-cam installed in her car to record all exchanges of the child. One spring morning the couple agreed on a rendezvous point for Aramazd Andressian to pick up his son for a trip to Disneyland. Piqui, 5, and his father had a full week to spend together.

"He was supposed to return the child after seven days and the return was supposed to take place in San Marino at 8 that morning," said Det. Aguilera.

Ana arrived at the designated location anxious to see her son.

"She waited for hours at this drop-off place in San Marino to receive her child," said Aguilera.

But father and son never arrived. Ana had not heard a word from either of them.

"Obviously Ana became very, very concerned. She reported to the police that her son was missing," said L.A. County Deputy District Attorney Craig Hum.

Just a few miles west in South Pasadena, investigators were working another bizarre case. Someone had reported a man lying in the road. It was April 22, 2017. That man was Aramazd Andressian.

"Aramazd Senior was found in the parking lot at Arroyo Park in South Pasadena. He was near his car, which was an older model BMW," said Hum.

"He passed out," said Det. Aguilera. "He was found about 30 feet, 35 feet from the car."

"Aramazd Senior was semi-conscious and appeared to be somewhat delusional when he was found by a passerby," said Hum.

Court documents reveal Andressian's hands were scratched and his fingernails were filled with dirt.

"He had a small laceration or abrasion to the top of his head," said Aguilera. "He had some scratches to his forearms, his hands, and he complained of bruising to his ribs. No defensive wounds."

Little Piqui was nowhere to be seen -- and to make matters worse, his father appeared in no condition to explain why.

"He was also found to be under some other opiates, some other prescription medications as well," said Det. Aguilera.

Aramazd Andressian was transported to a hospital. When he came to?

"His initial statement to police officers when they responded to the hospital after he had been transported was he didn't know what happened," said Det. Aguilera.

Could Aramazd Andressian have lost his only child because of a pill-induced stupor?

"He kept on saying 'I just fell asleep and woke up and detectives were talking to me,'" said L.A. County Sheriff's Detective Marc Boisvert.

Police documents show Andressian made a curious comment to the booking officer: "I bet they think of me like some kind of Casey Anthony." And then stated he was "probably all over the news by now."

"He never asked about the condition of his son or whether or not his son had been located," said Deputy D.A. Craig Hum.

Andressian turned the focus on his ex-wife as a possible suspect.

"He felt he had been set up," said Det. Boisvert. "Anytime we would question him, he would go back and ask us to look at Ana. He would start talking about the divorce, how contentious it was, that he had been followed."

Police held Aramazd Andressian on suspicion of child endangerment and child abduction -- but not for long. They had to cut him loose.

"There just wasn't enough evidence to arrest him and to try him," said Craig Hum.

"He's very happy to be out of custody so that now he can focus his sole attention on trying to find his son," said Andressian's attorney Daniel Nardoni.

"At this point we're treating this as a missing-person investigation," an official told a reporter.

Where was Piqui Andressian? Was he dead or alive? A massive 24/7 search was launched. The 5-year-old disappeared after a visit with his father to Disneyland. Piqui was last seen by his mother about 8 a.m. on Saturday, April 15, 2017.

"He can't think of anyone that would harm him," Andressian's attorney Daniel Nardoni told a reporter.

Would he harm him?

"Absolutely not," said Nardoni.

Aramazd Andressian Senior had no criminal record.

"Never been arrested before, never even received a speeding violation or any kind of ticket," said L.A. County Sheriff's Homicide Detective Louie Aguilera.

But authorities suspected Andressian did harm his child, and even though they didn't have the evidence to arrest him, they never let him out of their sight.

"What the detectives did was spend the next two months just building a case, piece by piece, watching his behavior, talking with other people who knew him," said L.A. County Deputy D.A. Craig Hum.

One thing was clear: While Piqui's mother worked day and night to find her son, for Aramazd Andressian, finding his son was not a priority. Partying in Las Vegas was.

"There was even an occasion where he went skydiving," said Hum.

"Right from the beginning within a week he was at the T-Mobile Arena watching a boxing match, from going there to prostitutes, to skydiving, the amount of drugs he was using out there," said Det. Marc Boisvert. "Everything was just surreal with his daily activities of someone who had told investigators that his son just magically disappeared."

Suspicion grew deeper when cellphone records showed Andressian turned off his phone just before the trip to Disneyland.

"No pings at all, and he planned this, and we knew he planned this," said Det. Aguilera.

Aramazd Andressian Sr. had created a will just days before the visit with his son. His older model BMW was an investigative gold mine.

"His car was found doused in gasoline. The interior was fully doused, the exterior was fully doused," said Aguilera. "There were two gas containers inside the car and he had a rag sticking out of the gas cap."

Investigators found knives and an LED lantern, still lit.

"That told us whatever he did with his child, he did under the cover of darkness," said Aguilera.

There was a child's sweatshirt with a white film on the back, which appeared to be vomit. And then, a startling and emotional discovery.

"There was an ultrasound picture of Piqui directly on the front dashboard under the radio, and we found that significant," said Det. Boisvert.

He was holding on to the first image he had of Piqui in this world.

Now detectives were working under the theory that Andressian murdered his child and had planned to kill himself. But they had to prove it.

Was DNA evidence used at all in this case?

"There was no DNA at all," said Aguilera.

What about computer forensics?

"We found a couple of computers, and a huge concern to us in the middle of this investigation was that he was searching wilderness areas in Santa Barbara County," said Det. Aguilera.

It was a significant clue. Detectives believed the internet search of secluded, heavily wooded areas two hours north was part of a calculated plan.

"He was searching for a place to bury or leave his son's body," said Det. Aguilera.

Search teams scoured 30 miles of terrain, as well as nearby Lake Cachuma. Police gathered multiple surveillance images recorded in the lake area, and they're troubled by what they see -- or in this case, what they don't see.

"All our surveillance, we did not see Piqui at all, we only seen the father the entire time," said Det. Aguilera.

Investigators were certain Piqui was dead, and they had developed a timeline, believing Aramazd Andressian leaves Disneyland with his son at 1 a.m. It takes him five hours to arrive at the Lake Cachuma area, where detectives say he murders his child and disposes of him in a remote wooded area. He reappears at 8 a.m. on a surveillance camera at the lake. Andressian Sr. is alone. Then he drives to South Pasadena, where police find him unconscious at 6 a.m. the next morning.

"His intentions were to kill himself after he killed the child," said Det. Aguilera. "He was going to light that car on fire. He was going to take as many prescription medications as he can, to the point he's about to pass out, and then light that car on fire."

He passed out before he could light it on fire.

Two months after little Piqui Andressian went missing, police arrested his belligerent and defiant father in Las Vegas on a no-body murder charge.

"He was on prescription medications. He wasn't clear-headed. He was hostile towards us, he called us animals," said Det. Aguilera. "He said something to the effect of, We spent $7 million to find this child and we still couldn't find him."

And so much for those plans to kill himself. Andressian had bleached his hair and applied for a passport.

"Detectives were concerned that Aramazd Senior might try to flee to Iran or to Russia to avoid being extradited back to the United States," said Deputy D.A. Craig Hum.

The California father was finally charged with the murder of his 5-year-old after spending the last few weeks of his freedom partying in Las Vegas.

After two months of reckless self-indulgence in Las Vegas, Aramazd Andressian Sr. was arrested for the murder of his son, even though 5-year-old Piqui's body was yet to be found.

Los Angeles County Sheriff's Homicide Detectives Louie Aguilera and Marc Boisvert had worked the case tirelessly from the beginning. They were hoping to see an end.

"We interviewed him at the jail in Las Vegas, and that interview once again went nowhere," said Det. Aguilera.

"Once he was brought back to L.A. County, his initial plea at arraignment was not guilty," said Det. Boisvert.

Andressian gave up nothing about the location of his son, punishment for Piqui's family, still clinging to a sliver of hope, many believing perhaps Andressian Senior's mother might be hiding the child.

"No matter how unrealistic it might be, I think that victims' families will hold on to hope as long as they possibly can," said L.A. County Deputy District Attorney Craig Hum. "Just the way he behaved was clear that he knew that nobody was going to find his son alive."

It was time for the child's mother, Ana Estevez, to face the crushing reality.

"I was brutally honest with her. I told her 'I hope I'm wrong, but I think he killed your son,'" said Det. Aguilera. "I didn't want to give her a false sense of hope."

Ana Estevez was mired in grief, but displayed unwavering dignity, continuing to search for her child.

"My son knew me as a strong woman, a woman who didn't give up, and I need to be that person for him. That's who he knew, and that's who he would expect me to be, and that's who I'm trying to be," Ana Estevez told Crime Watch Daily.

With their suspect behind bars, detectives are left pondering just what kind of calculating chess game Andressian would force them to play in order to get Piqui home. But in this case, a shocking, almost surreal turn of events came about: There would be no gamesmanship or resistance. Aramazd Andressian Senior's defiance was spent.

"He wanted to talk about the case and he wanted to let me know where his son was buried, and what happened," said Det. Aguilera.

There was no plea deal offered to him, no promises of leniency -- nothing. Andressian, stunningly, wanted to confess. Then, what he told cops was nothing short of evil.

"The manner in which he killed him was particularly cruel," said Craig Hum. "His son was asleep in the car seat in the back of the car. His father, who was supposed to be protecting him, who was supposed to be taking care of him, stops the car, gets out of the car and then uses Aramazd Junior's sweatshirt to smother him. And not only that, but once he had finished smothering his son and let go, when he let go, his son, his body was still twitching, so Aramazd Senior smothered him again."

And finally Andressian told sheriff's detectives where to find little Piqui.

"The area was an observation point for the Bradbury Dam, it's called Vista Point. Its mountainesque," said Det. Aguilera.

Piqui had been left alone in the cold, remote elements for two long months.

Was he buried at all?

"He wasn't, he was laid out under a tree with some shrubbery on top of him," said Det. Aguilera. "The suspect had changed him and put him in pajamas and rested him there up against a tree."

A wretched, unthinkable murder of his own flesh and blood. But why did he confess? The prosecution's case was strong, but largely circumstantial, and no-body murder cases are rare.

Was that to save the public, the family from a trial, or did he do this for selfish reasons?

"Aramazd Senior was and actually is one of the most selfish people I've ever seen," said Hum. "It's our belief that he pled guilty because he knew that if there was a trial, all of the horrible details about his behavior would become public in a trial, and he wanted to avoid that."

Cops knew Andressian's pride and image was more important than his son or his freedom.

"I think it's what we did for the months prior. I think we broke him down," said Det. Aguilera. "We made it a point to have the media on board with everything we did, and we made it a point to exploit him for what we knew he was. He didn't like being in the suicide vest that you see him wearing in court. It's demeaning to him, and he hates it, and he asks me 'What you can do to get me out, get me out of this suicide watch? I don't want to be wearing this, this is embarrassing.'"

If Aramazd Andressian Sr. thought pleading guilty would spare him further public humiliation, he was sorely mistaken.

"My family has lost a piece of themselves. I have lost a piece of myself. Today is my birthday. My first birthday in the last five years without my baby cousin," Alexandria Estevez said in court.

It was sentencing day, and Piqui's family flooded the courtroom with raw, heart-crushing emotion.

"For Aramazd Andressian Senior, I pity you. You are a failure as a father, you are a failure as a man, and you are a failure as a human being," Ana Estevez said in court. "I hope you relieve the image of you murdering my baby every day for the rest of your insignificant life. And when you die, may your dark soul burn in the eternal flames of hell, where I have no doubt that justice will be served on you both in this life and the next."

Then the words no one expected to hear.

"My client would like to make a brief statement, your honor," said Andressian's attorney.

The riveted courtroom was eager to hear what this child-killer had to say. But he changed his mind.

"Mr. Andressian, you do have the right to make a statement. That statement must be under oath and subject to cross-examination. Do you wish to make a statement or to give any testimony, or not?" said L.A. Superior Court Judge Cathryn F. Brougham.

Andressian: "No."

Instead, Andressian's attorney tried to show good faith on his client's part.

"I can't think of a situation that I know of or have been in in 20 years where a plea of guilty to first-degree murder happened so quickly. That was my client's wishes from the very beginning," said an attorney for Andressian.

That comment that seemed absurd to family members and cops, considering the two months Andressian partied in Vegas while his son's body rotted away.

Nothing Andressian or his lawyer had to say would have made any difference. The sentence was set in stone.

"As to count one, violation of Penal Code Section 187a, murder in the first-degree, premeditated murder, the defendant is to be sentenced to state prison for 25 to life," said Judge Brougham.

Aramazd Andressian Sr. received the maximum sentence for a non-death penalty first-degree murder case.

"There just wasn't enough evidence to prove the special circumstance that would have subjected him to the death penalty. Believe me, if there was, we would have filed," Deputy D.A. Craig Hum said in a news conference.

When it was finally over, Ana Estevez graciously paid tribute to 27 different police agencies who dedicated themselves to a very difficult case. Especially the two L.A. County Sheriff's Homicide detectives who wouldn't sleep until justice was done.

"I've said it before and I'll say it again: You are my heroes, and I am eternally indebted to you both," said Ana Estevez.

But there's another bitter element to this horrific story: Ana Estevez had fought Child Services like a warrior for sole custody of her child. She so feared Andressian's ill intentions that she had a dashboard camera installed in her car so there was a record of every interaction. In the end, her fight for full custody was denied. Estevez points a harsh finger at social workers.

"I believe you are partially responsible for my son's death," Estevez said in the news conference outside court.

Her anger toward Child Services workers and the juvenile justice system was so deep that she delivered a public bashing to those she was forced to deal with.

"How dare you say that once a case is closed, you do not reopen it, even after being asked repeatedly to further investigate allegations," said Estevez. "How dare you say that Aramazd Senior kicking my son on his bottom and pinching his cheeks and yelling in his face that he was a bad boy was not enough to change custody, that it was simply bad parenting?"

As for Aramazd Andressian Sr., the sole purpose for his despicable actions was pure revenge.

"It seemed clear that Aramazd Senior's hatred for Ana Estevez, the mother of their child, was so strong that he was willing to do anything he could to hurt her," said Craig Hum.

Andressian has hurt her irreparably and eternally, but Ana Estevez will not allow him the power to make her lose her soul or forget what she plans to do to keep the legacy of her precious son alive.

"He's a bright beautiful ray of sunshine in the lives of everyone who met him, and even those who haven't, because he's brought a lot of love to a lot of people," Estevez tells Crime Watch Daily.

"He may have been robbed of his life, but he wasn't robbed of his legacy. It will live on forever," said Alex Estevez, Piqui's cousin.

"Unfortunately the decisions that were made in my court case gave my ex-husband the tools to murder my son, and that should never happen," said Ana. "Every person needs to be an advocate, regardless of whether or not they have children. Everyone needs to protect children."

Ana Estevez is currently working with lawmakers in Washington, D.C., pushing for new guidelines in custody cases. If passed, it would change the way the courts make custody decisions when violence is alleged. The new House resolution is receiving praise from Los Angeles County Sheriff Jim McDonnell.

"I think the real positive is what Ana is trying to do now, is trying to ensure that this doesn't happen to other kids, to other families," said Sheriff McDonnell.

Since 2008, 624 children have been murdered by a parent in the United States.