A Ramsey County sheriff's deputy investigating a student's alleged school shooting threat that revealed an arsenal of weapons at a Vadnais Heights home testified Monday that a top school official believed that the threat was not credible but that she didn't include the information in a search warrant.

Deputy Jessica O'Hern could not remember the school official's name during her testimony, and when she tried to refresh her memory by reviewing her reports, revealed that she had not recorded the name.

"She tends to sweep things under the rug," O'Hern said of the unnamed administrator.

O'Hern testified at a hearing for the boy's mother, Lisa Stowe, who was arrested and charged in March with one count of gross misdemeanor negligent storage of a firearm based on evidence collected at the family's home, including dozens of firearms, thousands of rounds of ammunition and at least one explosive device, according to authorities.

Stowe's attorney, Sam Surface, filed a motion challenging the search warrant, alleging there was no probable cause for it, and that if the court believes there was, evidence should still be suppressed because of O'Hern's "deliberate" omissions.

"[O'Hern] kept it out because she knew if she included it, she was a lot less likely to get a warrant," Surface said of the administrator's statements. "I think it calls into question [O'Hern's] credibility today."

A cache of weapons and explosives were found in the home of a Vadnais Heights teen after threats were reported.

Stowe's son, who was 13 at the time and whom family members have said is autistic, allegedly made threats on Feb. 28 that he would shoot classmates at the Academy for Sciences & Agriculture High School.

A classmate's mother alerted authorities, who executed O'Hern's search warrant on March 2 and then a second one later that same day.

Steven Tallen, who is prosecuting the case for the city of Vadnais Heights, asked O'Hern why she left out the administrator's assertions.

"I didn't feel that my opinion should go in there — that I didn't believe the school was taking it seriously," O'Hern said.

The deputy said a different administrator was concerned about the threat, and that authorities had an obligation to investigate.

Surface wrote in his motion that authorities had no information Stowe's son had ever been seen with a gun or had access to guns. He also noted that the boy was known for telling "falsehoods."

The sheriff's investigation of the Stowe family was caught in a storm of events: It came just weeks after a former student shot and killed 17 students and staff members and injured 17 others at Marjory Stoneman Douglas High School in Parkland, Fla., on Feb. 14. It also pitted Sheriff Jack Serier in an election year against a formidable opponent, former Ramsey County Sheriff Bob Fletcher, who criticized Serier's handling of the case. Both are running for sheriff in November.

In June, the Ramsey County Attorney's Office dismissed all counts filed against Christopher Stowe — two felony counts of prohibited possession of machine guns and short-barreled shotguns and one count of gross misdemeanor negligent storage of firearms. Authorities misidentified a gun as fully automatic.

The Sheriff's Office said in June that Christopher Stowe could still face federal charges, but his attorney, Bruce Rivers, said Monday that the U.S. Attorney's Office told him no charges would be filed.

"When this happened, the Parkland shooting was fresh in everyone's mind, and rather than go with the law, the sheriff went with his gut," Rivers said. "They treated these parents horribly."

Tallen is reserving a decision on possible lower-level charges against Christopher Stowe pending his wife's case, Rivers added.

A judge has not ruled on Surface's motion.

Chao Xiong • 612-270-4708 Twitter: @ChaoStrib