Witness Testifies He Heard Former Deputy Tom Fallis Say He Shot His Wife

— -- In a frantic and disturbing 911 call placed just hours after Tom Fallis was seen dancing with his wife Ashley at a New Year's Eve party in 2012, Fallis can be heard begging police to help him.

"My wife just shot herself in the head, please help me! Please help me!" Fallis screams.

Ashley's death was initially ruled a suicide by five separate law enforcement agencies, but now four years later, Fallis, a former corrections deputy, is on trial for her murder, accused of shooting and killing her that night after they hosted a party with family and friends at their home in Evans, Colorado.

New witness statements surfaced in 2014 and led to a grand jury investigation. Fallis was ultimately indicted for second-degree murder in November 2014.

Powerful witness testimony was heard in court for the first time this past week. Ashley's mother, Jenna Fox, testified that she never accepted the ruling that her daughter committed suicide.

Nick Glover, who was the Fallises' next door neighbor and was just 15 years old at the time of the shooting, testified that he heard through an open window Fallis confess to the crime to two people.

"What I heard him saying was, 'Oh my God, what have I done? Oh my God, what have I done?'" Glover said on the stand. "He proceeded to say, 'I shot my wife.'"

When asked how certain he was it was Fallis' voice, Glover testified that he was "100 percent" certain. "You can't hear something like that and forget about it," he said. "I mean, that's going to be embedded in your mind for years to come."

The two people Fallis was allegedly talking to that night were his parents, Jim and Anna Fallis. But in testimony they gave last week, they denied that Tom confessed to them. His parents said they left the New Year's party earlier that evening but came rushing back after getting a phone call and a text from their son saying, "I need you now."

Anna testified that she comforted her son, who was distraught, and said he never told her he had shot Ashley.

But Ashley's mother gave a very different view of how Fallis treated her daughter at that New Year's party.

"At the very end of the night, I think that his behavior towards her was very threatening and very volatile and very scary," Jenna Fox testified.

According to the grand jury indictment, Fallis became "irate" at the end of the New Year's Eve party, "stormed into the master bedroom," grabbed a "9mm handgun" and shot Ashley.

Fallis told police at the time he was innocent and has pleaded not guilty to the charges. During his interrogation with investigators, Fallis screamed, "I didn't shoot my wife."

But Fox didn't believe him and worked with Denver TV station KDVR to take a closer look at the case. One of the key witnesses unearthed in the news station's investigation was a neighbor named Chelsea Arrigo. Kathy Glover, Nick Glover’s mother, testified that Arrigo called her the night of the shooting and asked if she had called the police. Kathy said she told Arrigo she had not called the police, and asked Arrigo why she should have.

“She said, ‘Because your neighbor just shot his wife,’” Kathy Glover testified. “I said, ‘What?’ and she said, ‘I could hear her screaming, “Get off me! Get off me!”’”

But when she took the stand, Arrigo testified that she didn't recall saying that to Kathy.

Still, Ashley's family maintains that law enforcement purposefully omitted information in reports on her death in order to protect "one of their own."

"They never pursued her death as a homicide," Fox testified.

Evans Police publicly deny any wrongdoing and say there was never a cover-up. They maintain this case was thoroughly investigated in 2012.

Two of the Fallises’ three young children may have witnessed something the night of their mother’s death. One of them drew pictures for investigators showing their parents in the master bedroom and reportedly said at the time of questioning that she heard them having an argument.

"The fact that one of their daughters is saying, 'Dad seemed mad,' becomes very important here and fits in with the prosecution's theory of the case -- that he was enraged and that he killed her," said Dan Abrams, ABC News' chief legal affairs anchor.

But the kids told investigators they did not see their father shoot their mother.

"This is not an easy case for prosecutors," Abrams said. "People like to think that eyewitness testimony is the best kind of evidence you can have in a case when in reality the best kind of evidence is DNA."

Regardless of the outcome of the trial, Ashley's mother has a pending civil suit against several law enforcement agencies that handled the investigation into her daughter's death.

Fallis has pleaded not guilty in the death of his wife.