Boulder mass killing suspect who reportedly criticized Trump for his immigration stance was ‘previously known’ by FBI: Report

The Federal Bureau of Investigation was aware of accused mass killer Ahmad Al Aliwi Alissa's potentially dangerous background even before he carried out the massacre that took the lives of 10 people in Boulder, Colorado, according to reports.

What are the details?

Tuesday, the New York Times reported that 21-year-old Alissa was "previously known" because he reportedly had connections to another individual who was under investigation by the agency.

According to the report, the suspect was convicted of misdemeanor assault against another student at his high school in 2018. When questioned about his assault, Alissa reportedly told authorities that he carried out the attack in response to "insults and ethnic taunts."

"Fellow students recall him having a fierce temper that would flare in response to setbacks or slights," the report noted.

Alissa, the Times noted, purchased a firearm on March 16 — just days before the deadly attack.

Alissa, who was born in Syria in 1999, lived "most of his life in the United States" according to Boulder County District Attorney Michael Dougherty.

On Tuesday, a man purporting to be Alissa's older brother told the Daily Beast that his brother was "very anti-social, paranoid, mentally ill, and obsessed over someone being 'behind him' or 'looking for him.'"

He told the outlet, "I feel so sorry for the people that were shot by Ahmad. This was something I would have never expected Ahmad to do. What he did ... why, I don't know."

A woman who reportedly identified herself as Alissa's sister added, "We're shocked. He is a nice, quiet brother."

Anything else to know?

The Daily Beast also reported that a Facebook page believed to belong to Alissa addressed his Islamic background.

In a 2019, a post on the page read, "Yeah if these racist Islamophobic people would stop hacking my phone and let me have a normal life I probably could."

The outlet added, "On Facebook, his politics appeared mixed throughout several camps. He shared an article rebuking Donald Trump's stance on immigration, but also posted about his own opposition to gay marriage and abortion."