Cruz bought AR-15 3 days after being kicked out of school

The gunman who slaughtered students and teachers at a Florida high school picked up his alleged murder weapon just days after being kicked out last year.

Nikolas Cruz is charged with killing 17 people at Marjory Stoneman Douglas High on Wednesday, where he brought his legally purchased AR-15 assault rifle into the halls where he was previously known for disciplinary problems.

Authorities on Thursday released a timeline of the Parkland shooting, including the 19-year-old shooter’s post-massacre stops at Walmart and McDonald’s before his arrest.

But a report from WPLG early Friday illuminated the timeline that went further back, including school administrators asking for a “threat assessment” on Cruz back in January 2017.

A copy of his disciplinary records seen by the station show that the future attacker was involved in an assault at the school in mid-January, which caused administrators at Douglas to ask the school board to do the assessment.

RELATED: A timeline of how the Florida high school shooting unfolded

It is not clear whether the assessment was done or what it concluded.

Broward Schools Superintendent Robert Runcie said Thursday that the school received “no warning, no hints, no tips” about the impending violence, despite some classmates telling media that Cruz had an obsession with weapons and they joked about his likelihood to shoot up the school.

Cruz, who had an extensive disciplinary record for profanity and fighting, withdrew from the school on February 8.

Three days later he walked into Sunrise Tactical Supply, in nearby Coral Springs, and purchased the weapon that he would bring back to the school more than a year later.

Stuart Kaplan, an attorney for the company, told reporters outside the store on Thursday that Cruz passed a background check including answering questions about his mental health.

Republicans including President Trump have blamed the shooting on not reporting "warning signs," despite the fact that Cruz was well acquainted with the discipline systems of his schools.

Florida law prohibits firearms purchases for a number of categories, including felony convictions, being judged "delinquent" as a minor and being "adjudicated mentally defective."

RELATED: Vigils held after deadly shooting at Marjory Stoneman Douglas High School in Florida

Kaplan added that laws should be changed to raise the minimum age for buying assault weapons to 21.

Douglas Rudman, a lawyer for the family that owns the shop, said that the shooter “fell through the cracks” and was not part of any database.

It is not known how long Cruz was planning his shooting, which authorities have said was designed to maximize death.

Previous school shooters have spent lengthy periods prepping to inflict pain on their classmates, with Dave Cullen’s book “Columbine” pointing to the fact that Dylan Klebold and Eric Harris mentioned their massacre nearly a year before they killed 13 people.

A video captured by a neighbor showed him shirtless wearing a pro-President Trump “Make America Great Again” hat, shooting at targets in his backyard with a BB gun in the months before the shooting.

Cruz also used smoke grenades in his attack, though it was not immediately clear where he got them.

With News Wire Services