Police on Sunday identified the shooter who killed three people at a Dollar General store in Jacksonville, Florida, on Saturday afternoon in what they say was a racially motivated attack.

Ryan Christopher Palmeter, 21, entered the store near Edward Waters University around 1 p.m. carrying an "AR-style" rifle, a handgun that had swastikas on it and was wearing a tactical vest, Jacksonville Sheriff T.K. Waters said at a news conference.

Waters said Palmeter authored several documents including one to his parents, one to the media and one to federal agents before he shot and killed three Black victims − two men and a woman −and killed himself.

"Portions of these manifestos detailed the shooter's disgusting ideology of hate,” Waters said. “Plainly put, this shooting was racially motivated and he hated Black people.”

The FBI is investigating the shooting because the killings were a hate crime, FBI officials said, the Jacksonville Florida Times-Union reported.

Jacksonville shooter drove to Edward Waters University before Dollar General shooting

Police and university officials said Palmeter drove to Edward Waters University, the first historically black college in Florida, before he drove to the Dollar General store. 

A. Zachary Faison Jr., the university's president and CEO, said Palmeter was confronted "almost immediately" by campus security, he said in a video posted to X, formerly Twitter.

Palmeter then put on an armored vest, got back into his vehicle and drove away, Faison said.

Shooter involved in 2016 domestic call in Clayton County

In 2016, Palmeter was involved in a domestic call, but he was not arrested, Waters said. A year later, he was temporarily detained for emergency health services under Florida's Baker Act, the Jacksonville Florida Times-Union reported.

"He acted completely alone," Waters said.

President Joe Biden: 'White supremacy has no place in America'

In a statement Sunday, President Joe Biden said federal officials are "treating this incident as a possible hate crime and act of domestic violent extremism."

"Even as we continue searching for answers, we must say clearly and forcefully that white supremacy has no place in America," Biden said. "Silence is complicity and we must not remain silent."

Contributing: Teresa Stepzinski and Gary T. Mills; Jacksonville Florida Times-Union