The 20-year-old identified as the shooter who nearly killed former President Donald Trump Saturday evening was a dietary aide at a Pittsburgh-area nursing and rehab facility, authorities said Sunday. 

Thomas Matthew Crooks’ job performance was appropriate and a pre-employment background check did not raise any red flags, the facility’s administrator said in a statement provided to McKnight’s Long-Term Care News Sunday.

Crooks was immediately shot dead by secret service agents after the attack, which took place shortly after 6 p.m. ET. Trump suffered a grazed ear, while one rally attendee was killed and two others were injured. Officials did not specify further details of those situations but noted that Crooks apparently took eight shots before being killed. 

The local sheriff’s office said an officer encountered Crooks on a roof building but had to back down a ladder without drawing his weapon. Crooks then rushed off some shots, according to an AP account.

It was not known how long Crooks worked at Bethel Park Skilled Nursing and Rehab Center, nor what his specific duties were. The center said it was cooperating with law officials and would not comment beyond its formal statement.

“We are shocked and saddened to learn of his involvement as Thomas Matthew Crooks performed his job without concern and his background check was clean,” facility administrator Marcie Grimm said in the statement. “Due to the ongoing investigation, we cannot comment further on any specifics. Our thoughts and prayers go out to former President Trump and the victims impacted by this terrible tragedy. We condemn all acts of violence.”

A spokeswoman for the for-profit center’s owner, Genesis HealthCare, referred a McKnight’s inquiry back to Grimm’s statement.

The 160-bed center is in a southern suburb of Pittsburgh, about an hour south of where the shooting took place and about a mile from the shooter’s home. Neighbors occasionally saw him walk to work, according to local reports.

In its most recent Nursing Home Compare figures, the Bethel Park center’s average occupancy was just under 90% and it was rated 4 stars.

Its website lists inpatient rehab, out-patient rehab and on-site dialysis as featured services.

A coworker who declined to be named in a CNN report described Crooks as “the sweetest guy” who just last week was helping “a bunch of sick old ladies (to) put ranch on their salads.”

The colleague, who also went to school with Crooks, said he didn’t express political views at work and wasn’t “a radical.” They called him “a really, really good person that did a bad thing and I just wish I knew why.”

Subsequent news reports at mid-week said that Crooks had told his supervisor he needed Saturday off for something important, and he told co-workers he expected to see them at work Sunday.

Various news reports reveal neighbors and former classmates depicting Crooks as a relatively reserved figure who would occasionally wear fatigues to school, which at least one former classmate called not uncommon for the area. One classmate who did not share any classes with Crooks said the shooter was an “outcast” who was “bullied almost every day,” a description that was not matched by at least one student from another report who did share classes with him.

Crooks was a member of an area shooting club but was never a  member of his high school’s rifle team. He was turned away because he was “a bad shooter,” according to an ABC News report that related observations of the team’s current captain. Crooks used a high-powered rifle owned by his father, who was not being portrayed as a “straw man” buyer for his son, authorities said Sunday.

Officials said they were examining Crooks’ telephone and background Sunday for clues about a possible motive. He was registered as a Republican, according to state records cited by various outlets, but earlier this year he donated $15 to a Democratic organization.

Authorities also said Sunday they had not uncovered any signs of erratic social media behavior or other tip offs that he might become violent.