The father of a 13-year-old Vadnais Heights boy who was arrested for allegedly threatening to shoot up his school plans to challenge the probable cause that led to his own charges of having illegal firearms and loaded guns openly left in his house.

Attorney Bruce Rivers called the arrest of his client, Christopher Lloyd Stowe, 41, "a classic case of government overreach" and said there was an insufficient basis to believe Stowe's son planned to fire guns at the Academy for Sciences & Agriculture in Maplewood.

Rivers said he will also challenge the legality of the search warrant Ramsey County sheriff's deputies used to search the boy's Vadnais Heights house.

Stowe, a plumber, who has since been released without posting bail, arrived at the Ramsey County Law Enforcement Center on Tuesday for a court hearing, but instead of the hearing, Rivers agreed to waive the rule requiring an omnibus hearing within 28 days of an arrest.

A new hearing date was set for April 12, and at that one, Rivers said, he will ask for a contested evidentiary hearing to challenge the basis for Stowe's arrest.

He said Stowe's son is autistic and was watching a cartoon on his phone when a bully asked the youth whether he was going to shoot up the school.

"He was asking a bunch of leading questions," Rivers said. "Anyone who knows this kid knows he wouldn't hurt a fly."

The boy was arrested on one felony count of threats of violence. The Sheriff's Office said it found firearms in the home including machine guns and short-barreled shotguns, two explosive devices and kits to convert weapons to automatic weapons.

Lisa Marie Stowe, 40, the boy's mother, was charged with one gross misdemeanor count for negligent storage of firearms. The boy was released and is staying with relatives.

The incident and arrests occurred about two weeks after the Feb. 14 school shooting in Parkland, Fla., that left 17 students and adults dead.