UPDATE August 12, 2019:

Pam Hupp will spend the rest of her life behind bars for a 2016 murder. Hupp appeared in a St. Charles County courtroom Monday, Aug. 12, 2019, to hear the sentence, KTVI reports.

In June, Hupp cut a deal to avoid the death penalty in the murder of Louis Gumpenberger. Hupp entered an Alford plea, acknowledging county prosecutors had enough evidence to convict her of murder.

MORE: Pam Hupp gets life sentence for 2016 murder - KTVI

UPDATE December 18, 2018:

Pam Hupp’s defense team made its final argument this week on what to keep out of her June trial, KTVI reports.

Pam Hupp’s lawyer wants no mention of the murder of her friend, Betsy Faria. It’s an unsolved case from 2011 in which Hupp benefitted from $150,000 in life insurance proceeds.

Hupp’s June trial, however, is focused on the shooting death of a man with disabilities in 2016. She told police Louis Gumpenberger invaded her home and she shot him in self-defense. Prosecutors say she lured him to his murder.

But it’s the 2011 unsolved Faria murder that’s the focus of current court arguments. Prosecutors say it’s relevant and goes to Hupp’s motive. They say Hupp was trying to deflect negative attention in the Faria murder and lured an innocent person, so she would look like a victim.

Hupp’s defense lawyer, Kim Freter, argued Hupp was never a suspect in the Faria murder and wrote in a filing this week, “The Faria evidence changes Pamela from a sixty-year-old woman with no prior convictions who shot a man in her home into a ‘serial killer’ responsible for two murders.”

Freter added, “The state is offering its unreliable, unproven, speculative, hearsay evidence in an attempt to paint Pamela as a person of bad character with the propensity to commit murder.”

September 28, 2016:

A woman confronts and shoots an intruder dead inside her home. But police say this was no attempted burglary. In fact the woman who claims she fired in self-defense is well-known to investigators in another famous murder case.

A woman has a gun in one hand and a phone in the other as she calls police to says she's shot dead a knife-wielding intruder in her home. And when cops arrive, it appears to be a clear-cut case of self-defense.

"She said she had no choice but to shoot and kill him," said KTVI reporter Chris Hayes.

But police find strange evidence that would ultimately tell a very different story, one that would uncover a sinister and twisted plot involving Russ Faria, someone police are already very familiar with, a man once convicted of murdering his own wife.

Chris Hayes has been covering the case for crime watch daily affiliate KTVI in St. Louis. He tells us he was beyond shocked when those first reports of the shooting came in.

Pamela Hupp, the woman who fired those shots, is already known to the media. And has she got a story to share.

"Hupp repeatedly told the officer that she did not know the subject who she just shot," said Tim Lohmar, St. Charles County, Missouri prosecuting attorney.

Hupp reportedly tells police she was sitting in her SUV in the driveway of her home when the man now lying dead on the floor had forced his way into the vehicle.

"The male subject put a knife to Hupp's throat and kept telling her that she was going to take him to the bank," said Lohmar.

But Hupp tells police she broke free, ran into the house, grabbed a gun off a nightstand And shot at him when he chased her into the bedroom.

TCD: Crime Watch Daily covers Pam Hupp cases

"Police say that she emptied her gun," said reporter Chris Hayes.

But when cops dig just a little deeper into the dead man's background they hardly find the typical profile of a would-be killer.

"The deceased male subject was positively identified by his fingerprints as Louis R. Gumpenberger," said Lohmar.

And as violent suspects go, he's as improbable as they come.

"This is a guy that can't drive," said Hayes. "He limps. He clearly looks like somebody struggling with a disability."

Chris Hayes spoke with Shannon Zoll, Gumpenberger's ex girlfriend and mother of his two children.

"He was in a car accident 11 years ago and he's got nerve damage down the left side of his body," said Zoll.

But investigators can't put the pieces of the puzzle together until they learn of another police report filed shortly before the shooting.

"Six days prior to the death of Gumpenberger, this subject reported a white female randomly pulled up," said Lohmar.

Surveillance video would later confirm that woman was Pam Hupp.

"The woman inside the SUV said that she was a producer from the 'Dateline' television show and she tried to recruit this individual to go with her to do a sound bite for an upcoming 'Dateline' episode and was promised $1000 in cash," said Lohmar.

Oddly enough, police find almost that same amount of money in one of Gumpenberger's pockets. And they start to wonder if maybe Hupp used the same "Dateline" story to get Gumpenberger into her car.

Cellphone records do place Pam right outside his apartment building shortly before he was killed.

"The evidence seems to indicate that she hatched a plot to find an innocent victim and to murder this innocent victim in an apparent effort to frame somebody else," said Lohmar.

It seemed Hupp specifically lured Gumpenberger to her home to make him look like a hit-man sent to kill her. But who would she be trying to frame? And why?

Inside the dead man's pocket, officers are stunned to find a telltale note.

"The note says something to the effect of 'Get Russ's money,'" said Hayes.

Hupp tells police the only Russ she knows is Russ Faria.

Already suspected in one murder, could Pam Hupp also be linked to the brutal slaying of Russ Faria's wife, Betsy?

Pam Hupp frantically calls police saying she's being attacked inside her own home by an intruder. But her story is quickly unraveling, and it's leading police straight down the path to one of the most infamous murder cases ever in the city of St. Louis.

Hupp had been a key and controversial player in a sensational murder Crime Watch Daily brought to national attention: The case of Russ Faria, who was convicted and ultimately exonerated of stabbing his wife Betsy to death.

It was at a house in the St. Louis suburb of Troy that Betsy Faria was murdered and mutilated just two days after Christmas in 2011.

Russ had returned home that evening to find Betsy dead from dozens of stab wounds, her arms nearly severed.

The medical examiner would ultimately find that Betsy had been stabbed 55 times. Detectives grilled Russ for days.

And Russ has an alibi supported by cellphone tracking records and four friends who all say he was watching movies with them at the time of Betsy's murder.

But police and prosecutors won't accept it.

Cops can't find a speck on blood on him or his clothing.

"They assumed that this was a crime of passion and the only person who would be so impassioned would be the husband," said Joel Schwartz, Russ Faria's attorney.

Despite what many say is a lack of any credible evidence against him, Russ Faria was charged with the first-degree murder of his wife.

And to Russ's horror and disbelief, he is ultimately convicted by a jury and sentenced to life in prison, plus 30 years.

"It was shocking," said KTVI reporter Chris Hayes.

Hayes says he had witnessed how Russ was seemingly railroaded by the police, the prosecution, and Pam Hupp. Hupp's testimony helped wrongly convict Betsy Faria's husband for her murder.

Chris Hayes launches an investigation with the St. Louis Post-Dispatch that would expose how Hupp had been overlooked as a suspect in Betsy's murder.

Hupp had been helping to care for Russ's wife Betsy, who was suffering from terminal cancer, and was actually with her the night of the murder.

Hupp had unexpectedly turned up at Betsy's chemotherapy session and insisted on taking her home that night. Hupp contradicts herself on what happened when she got to the Faria home in an audio interview with detectives the morning after the murder. Hupp digs a deeper hole for herself when she is further questioned by police, indicating she was in the house longer than she had initially said.

Hupp tells police she had left the Faria house by 7:30 p.m. and had called Betsy when she got home, a 45-minute drive away. But cellphone records show that call was made at 7:27 p.m. in the area of the Faria home. It was determined Betsy had been murdered between 7:20 and 9:41 p.m.

And yet police arrested Russ within a day. Not only was Hupp not considered a suspect, she was also their key witness.

Still more suspicion would fall upon Hupp when it was learned Betsy had removed Russ as the beneficiary of a $150,000 life insurance policy just days before her murder and replaced him with Hupp.

"I had no idea until the detectives gave me a letter when I was incarcerated in the jail," said Russ.

The prosecutors and the judge wouldn't allow jurors at Russ's trial to hear about the insurance policy or other evidence that pointed to Hupp as possibly being Betsy's murderer.

"I couldn't cross-examine her as to motivation, I couldn't cross-examine any of the other witnesses, the police officers regarding their lack of investigation on Ms. Hupp, and most importantly I couldn't get into the insurance proceeds," said Russ's attorney Joel Schwartz.

And it was that suppression of evidence and the investigation by Chris Hayes that helped Schwartz win Russ a new trial, where he was exonerated and freed after nearly four years in prison.

But even more damaging information would come out about Pam Hupp and that insurance policy when Betsy's daughters filed suit for the $150,000.

Astoundingly, Hupp wins the suit, with the judge ruling she can keep the $150,000 because that is what he believes Betsy intended.

But Hupp's questionable deeds had also brought her under increased scrutiny in Betsy's murder.

Pam Hupp is under siege. Prosecutors are suspicious that Hupp is the one who really killed Betsy Farias to collect on a $150,000 insurance policy.

Then, the stunning breaking news out of St. Louis in August 2016 that Hupp fatally shot Gumpenberger in her home.

"The handwritten note [located in Gumpenberger's pocket] appeared to be instructions to kidnap Hupp, get Russ's money and then kill Hupp in order to collect the rest of the $10,000," said St. Charles County Prosecuting Attorney Tim Lohmar.

"She wanted to make it sound like Russ put a hit on her," said reporter Chris Hayes.

"The police questioned me about it. I was just dumbfounded," said Russ Faria.

"Following an extensive investigation, at approximately 11 a.m. this morning, Pamela Hupp was arrested for the charges of murder first-degree, and armed criminal action," said O'Fallon Police Chief Roy Joachimstaler.

Prosecutors say they may seek the death penalty.

And now, since the alleged murder of Louis Gumpenberger, St. Louis County Police have decided to review the suspicious death of Hupp's mother, Shirley Neumann, who died when she tumbled through a third-floor balcony railing at her retirement apartment in 2013.

Hupp was the last person to see her mother alive.

Pam Hupp has pleaded not guilty to the murder of Louis Gumpenberger. At the same time, just hours after her arrest for that shooting:

"While in custody this morning just before noon today Pamela Hupp indicated that she needed to use the restroom," said Chief Joachimstaler. "While inside Pamela Hupp began stabbing herself on her wrist and in her neck with a ballpoint pen she had secreted on her person before entering."

Her booking photo captures her injuries. She survived the suicide attempt to stand trial for the murder of Louis Gumpenberger, as well as possibly being investigated for Betsy Faria's murder and the death of her mother.