Earlier Monday, Brad Beyersdorf, public information officer for the Bureau of Alcohol, Tobacco, Firearms and Explosives, confirmed that bomb technicians detonated "explosive materials" or components found inside Stewart's house Saturday. Beyersdorf did not specify what was found but said that "to characterize it as a bomb or device is not accurate at this time."
But Stewart's father, Michael Stewart, told The Tribune he believes the chemicals found by police were used by his son to grow marijuana, which apparently spurred the Weber-Morgan Narcotics Strike Force to obtain the search warrant they attempted to execute Wednesday night on Stewart's house at 3268 Jackson Ave. in Ogden.
Michael Stewart claims police "botched" the initial investigation into his son's marijuana growing activities.
"It's possible the authorities may have been relying on an informant who broke the law who was trespassing," Michael Stewart said.
He did not specify why he believes that but said he has spoken with his son's attorney, Randall Richards. Richards did not return messages seeking comment Monday.
Smith also said officers searching Matthew Stewart's house had found a photo of Stewart dressed "as a terrorist" with "some kind of bomb device."
"It was a recent photo, based on his current beard size," Smith said.
But Stewart's father said the photo actually shows his son in a Halloween costume that he wore three or four years ago.
"He was going to the party as Osama bin Laden," the father explained.
Michael Stewart has said that his son who suffers from depression and anxiety grew marijuana to self-medicate. The father also has noted that his son worked a graveyard shift at a Walmart warehouse and may have been sleeping when police arrived.
Matthew Stewart a decorated Army veteran suffered unspecified injuries during the gun fight that have been characterized as not life-threatening.
Smith said one of the anticipated charges will be for the cultivation of marijuana. Matthew Stewart also is suspected of eight counts of attempted murder, Smith said.
The prosecutor on Monday said he is "confident" friendly fire did not cause any of the officers' injuries. But he said that a number of police were wounded as they were giving aid to other officers or trying to remove officers from the scene.
Smith said he was prohibited by ethical considerations and the need to protect the integrity of the investigation from revealing many details of the shootout.
"We're still in the process of collecting evidence," he said. "We have a crime scene that is massive."
Part of the investigation includes an examination of dash-cam video from the patrol cars of responding officers.
"Every officer within 15 miles rushed to give aid," Smith said. "We are still trying to figure out who responded."
He said, however, there was no video of the strike force arriving at the home and the start of the shooting.
Asked why officers chose to go to Matthew Stewart's home, rather than approach him at work or at some other location, Smith noted that the strike force did not have a warrant for Matthew Stewart's arrest. They had a warrant to search his home, Smith said, "where they had probable cause to believe illegal activity was occurring."
Smith added that officers had made "a number of attempts to go to that house and do this as low-key as possible ... to get him to cooperate."
He added: "If they had been expecting to find weapons, it would have been a different warrant and a different approach."
Smith said that before breaking into Matthew Stewart's home about 8:40 p.m. Wednesday, the officers "announced a number of times that they were officers."
Agent Jared Francom, 30, was killed during the shootout. He was an Ogden police officer who served on the task force.
Five other strike force officers were wounded.
Three of the wounded officers were still hospitalized Monday.
Ogden Officer Kasey Burrell, 33, remained in a medically induced coma after surgery for gunshot wounds in his head and abdomen. He was in critical condition in the Intensive Care Unit of McKay-Dee Hospital, said hospital spokesman Chris Dallin.
Fellow Ogden Officer Michael Rounkles, 29, had improved to fair condition, Dallin said. Ogden police Officer Shawn Grogan was still listed in fair condition and was expected to be released later this week.
Weber County Sgt. Nathan Hutchinson was released from McKay-Dee Hospital on Sunday.
Jason VanderWarf, 37, a wounded Roy officer, was released Thursday after treatment at Ogden Regional Medical Center.
A funeral for Francom is set for Wednesday at the 14,000-seat Dee Events Center at 11 a.m. on the campus of Weber State University, 4450 Harrison Blvd. Interment will be at the Ogden Cemetery.
Police were still combing Stewart's home for evidence on Monday.
Sal Tavera, who lives immediately to the north of Stewart, called him a quiet guy who didn't talk much. But he was an OK neighbor, he said.
Twice Stewart flooded Tavera's basement while working on his sprinklers, but Stewart made it right.
"He said, 'Sorry, can you give me a couple of days to fix it?' and he did it," Tavera said Monday.
And during last month's big wind storm, a limb from one of Stewart's trees fell onto Tavera's patio, still partly attached to the tree. But Stewart cleaned up the mess.
"I really have nothing bad to say about him," Tavera said of Stewart.
When the shooting started Wednesday night, Tavera was home with his four children, ages 8 to 18.
"I grabbed my kids and went to the back bedroom, and we put our nose to the floor," he said.
Tavera said police officers were shooting from both his front and backyard.
When the shooting stopped and Tavera came outside, he said he saw a couple of wounded officers sitting on the sidewalk outside his house and another neighbor brought them water.
Tavera is now deciding whether to go to Francom's funeral on Wednesday.
"I feel so bad about it, I might go," he said.
Sheena McFarland contributed to this report.
Weber-Morgan Narcotics Strike Force
The 12-officer Weber-Morgan Narcotics Strike Force is a specialized unit whose primary focus is to investigate the use and distribution of illegal narcotics.
In 2011, the strike force served 111 search warrants, seized 34 pounds of methamphetamine, one pound of cocaine, two pounds of heroin, 23 pounds of marijuana and 6,600 marijuana plants, according to Weber County Attorney Dee Smith.
They also seized 124 illegally possessed firearms.