Stewart said he would enter the IRS facility in Ogden, where he used to be a security guard, and would "kill IRS employees" if they tried to collect taxes from him, the girlfriend said.
But Stewart's sister, Erna Stewart, said the search warrant doesn't show that her brother broke any laws. She added that her brother was not planning any attacks and that his political views are irrelevant.
"Isn't it his right to question everything in the universe?" Erna Stewart said.
The ex-girlfriend, Erna Stewart said, lied "out of vengeance" toward Matthew Stewart.
"He caught her in some lies," Erna Stewart said, declining to elaborate.
The two search warrants, executed in February, are the first to be released in connection with the Jan. 4 shooting that killed Weber Morgan Strike Force Agent Jared Francom. At least four other search warrants remain sealed.
One search warrant gave police permission to search Stewart's computer for evidence related to the shooting. Eynon wrote that he was executing that search warrant when "I observed multiple images consistent with child pornography." The detective did not elaborate. Eynon obtained the second search warrant to search specifically for child pornography.
Erna Stewart said Eynon's assertion was vague. She said someone gave her brother the computer and any questionable images were not his.
"Anything that was possibly found on that [computer] most likely is not going to be admissible in court," Erna Stewart said.
Stewart has been charged in 2nd District Court with capital murder and other felonies related to the shooting. He has not been charged with any crimes related to child pornography.
The fatal shooting occurred when the strike force went to Matthew Stewart's home at 3268 Jackson Ave. to execute a search warrant alleging he was growing marijuana at the residence. Court documents say the strike force knocked and announced their arrival and went inside when no one answered.
Stewart was hiding inside, emerged and began firing at police, court documents state.
In a jail interview with The Tribune, Stewart said he was asleep and never heard the strike force knock. He said his alarm clock woke him then he heard breaking glass and thought intruders were in his home. Stewart said he was shot twice in the exchange with police.
Fund gets state OK
Michael Stewart, Matthew David Stewart's father, said Friday that his family received a permit from the State of Utah to raise funds for his son's defense.
"We want to thank everyone that has donated thus far and hope everyone continues to support him in his endeavor to get a fair unbiased trial," Michael Stewart said.