Stewart was accused of opening fire on Weber Morgan Strike Force officers serving a search warrant at his Jackson Avenue home around 8 p.m. on Jan. 4, 2012. Agent Jared Francom was killed in the shootout, and five other agents were wounded. Stewart also was injured in the shooting.
On Wednesday, a judge rejected his defense attorneys' arguments that a police officer lied to obtain the "knock-and-announce" warrant served at his home.
"I just think [Wednesday's] hearing hit him really hard," Erna Stewart said. "I just think he couldn't bear it anymore."
Stewart's attorneys had asked 2nd District Judge Noel Hyde for a hearing to determine whether Weber Morgan Strike Force Agent Jason Vanderwarf included false or misleading statements when he asked for a search warrant related to marijuana cultivation.
Defense attorney Bernard Allen said Friday that Stewart took particular issue with Vanderwarf's statements in the search warrant that he saw evidence of humidifiers, bright lights and extension cords through the window of a side door into the basement of Stewart's house. In the motion, defense attorney Randy Richards said Stewart always kept a curtain over that window, and alleged that Vanderwarf may have gone into the backyard illegally and viewed the items from a rear window.
"I know one of the things about the case that he was very consistent on was that there was no way for police to see into the basement," Allen said of Stewart. "[The curtain] was never not attached ... He always felt the officers were being less than truthful about that."
During Wednesday's hearing, 2nd District Judge Noel Hyde ruled there was insufficient evidence for a hearing regarding the Vanderwarf's affidavit.
Erna Stewart said no one had been able to talk to her brother-in-law after Wednesday's hearing, adding that Richards was planning to visit the jail on Friday. She said her family was feeling down after court on Wednesday, believing it was "obvious" that Vanderwarf lied in the warrant, and upset that the judge refused to entertain the motion. If her brother-in-law felt more upset than they did about the denial of the motion, she said it wouldn't be surprising that he ended his life.
"It shouldn't come as a shock, but it really was," Erna Stewart said.
Stewart had pleaded not guilty to a charge of aggravated murder and seven first-degree felony counts of attempted aggravated murder for allegedly trying to kill other officers, and one second-degree felony count related to alleged marijuana cultivation. According to court documents, 16 pot plants were found in the home after the raid.
Allen said that while Stewart "was a little bit depressed" after Wednesday's hearing, he found it hard to believe that his client committed suicide.
"None of us were losing hope in the case," Allen said. "We didn't really sense anything. His whole family was there [in court Wednesday], and we had a long chat after the hearing with his family about the things we still had. It was a setback, but certainly not the end."
Allen said Stewart's attorneys want answers about conditions in the jail and how carefully Stewart was being monitored.
"Obviously, we will look into the details of it," he said. "It's a good family. They are incredibly supportive of Matthew and my heart certainly goes out to them. This whole thing has been a horrible ordeal for them."
According to testimony at his preliminary hearing, Stewart had told Weber County investigators that he thought the men inside his home were there to rob him, and that he only fired at the men dressed in black after he was shot at first.
But during a press conference Friday, Weber County Attorney Dee Smith countered those claims, saying that Stewart shot first at agents from a "concealed position" in the house.
Smith also said prosecutors believed Stewart knew he was firing on law enforcement evidenced when Ogden Police Officer Michael Rounkles entered the home in full police uniform, and was shot in the face.
"The evidence is very clear that he knew exactly who he was shooting at," Smith said.
During a preliminary hearing, the law officers testified that while they were dressed in black when they entered the home, each was wearing a police identifier.
Smith said ballistics of the crime scene have been completed, and that all 17 bullets that struck police officers that night were fired from Matthew Stewart's 9mm gun. The homeowner fired a total of 31 shots, Smith said.
Smith acknowledged Friday that many people, including Stewart's family, have been critical of police practices surrounding the botched warrant. He defended the officers Friday, emphasizing they only had a search warrant for the home not an arrest warrant so they could not approach Stewart at work, on his way home or in any other setting.
"The actions of these officers were heroic and they followed the law every step of the way," Smith said.
Stewart's family announced his death early Friday morning on his Facebook page. The statement primarily castigated law enforcement and the courts for how they handled the case.
"He was supposed to be considered innocent until he was proven guilty beyond a reasonable doubt," the statement read. "Unfortunately, this system has become so perverted that those people that are in power are able to lie and justify their actions after purposely violating someone's civil rights and the rights that were supposed to be protected by the Constitution of the United State of America."
The Stewart family has held several rallies calling for an end to police violence and home-invasion-style raids since the 2012 shooting. Erna Stewart, who has been at the forefront of many of these efforts, said in January that it was not difficult to fight for her brother-in-law because she felt there was no way that the caring, compassionate, quiet man she knew would intentionally fire at a law enforcement officer.
An investigation into Stewart's death will be conducted by the Utah Department of Public Safety, according to Smith. Weber County Sheriff Terry Thompson said Friday that protocol and policy were followed before Stewart's death, and that hourly visual checks were done.
Stewart was offered help from a mental health professional at the jail, Thompson said, but he refused.
"Mr. Stewart has been treated in a humane and professional way," Thompson said.
Stewart is the fourth suicide at the Weber County jail since last November.
Francom's widow, Erin Frisby Francom, released a short statement Friday on her husband's memorial page on Facebook. She expressed condolences for the Stewart family and supporters, saying that any death is difficult for those closest to the deceased, no matter the circumstance.
"Now that Mr. Stewart has done this, he will not have his day in court," Erin Francom wrote. "Nor will my children, the rest of my family or everyone else that has been affected. He now has to answer to a higher power and I will keep faith in knowing that."
The oldest of five children, Stewart had served as an Army multichannel transmission systems operator in North Carolina and Germany for four years. He was awarded the Army Achievement Medal and a National Defense Service Medal before leaving the military in 1998, an Army spokesman said. He worked as a security guard for the IRS before getting a warehouse job on the graveyard shift a Walmart in Riverdale, where he was employed at the time of the raid.
A May 2014 trial date had been set for Stewart.