BATON ROUGE, La. (AP) — A 23-year-old white Baton Rouge man arrested Tuesday was accused of killing two black men and firing on a black family in a string of attacks that police say may have been racially motivated.

A law enforcement official said they had found a copy of an Adolf Hitler speech at the home of Kenneth James Gleason, and investigators said DNA on shell casings and other evidence link him to the crimes.

Gleason was led away from the police department in handcuffs just before authorities there held a news conference to announce that he would be charged with first-degree murder in the shooting deaths last week of a homeless man and a dishwasher who was walking to work.

“I feel confident that this killer would have killed again,” interim Police Chief Jonny Dunnam said.

Gleason’s attorney, J. Christopher Alexander, said his client “vehemently denies guilt, and we look forward to complete vindication.” Alexander declined to say anything else.

Authorities found a copy of the Hitler speech during a search of Gleason’s home over the weekend, according to the law enforcement official who spoke to The Associated Press on condition of anonymity because the investigation was ongoing.

Asked whether police suspect race was a motive for the shootings, Sgt. L’Jean McKneely said: “We’re not completely closed off to that. We’re looking at all possibilities at this time, so we’re not going to just pinpoint that.”

District Attorney Hillar Moore said his office could seek the death penalty.

“It appears to be cold, calculated, planned (against) people who were unarmed and defenseless,” he said. “We don’t need to prove motive. There are a lot of things that are unanswered.”

No one was injured when Gleason fired multiple times into the home of a black family in his neighborhood on Sept. 11, authorities said. It’s not clear if Gleason knew the family.

In the other shootings, Gleason fired from his car then walked up to the victims as they were lying on the ground and fired again multiple times, police said. Neither victim had any prior relationship with Gleason.

The first fatal shooting occurred Sept. 12 when 59-year-old Bruce Cofield, who was homeless, was shot to death. The second happened last Thursday night when 49-year-old Donald Smart was gunned down while walking to his job as a dishwasher at a cafe popular with Louisiana State University students.

The attacks came at a time when Louisiana’s capital already was in the grips of a surge in violence. The number of homicides in East Baton Rouge Parish has already surpassed last year’s total of 62, The Advocate newspaper reported earlier this month.

“Baton Rouge has been through a lot of turmoil in the last year. Has there not been a swift conclusion to this case, I feel confident that this killer probably would have killed again,” the police chief said. “He could have potentially created a tear in the fabric that holds this community together.”

Racial tensions roiled the city in the summer of 2016 when a black man was shot to death by white police officers outside of a convenience store. About two weeks later, a black gunman targeted police in an ambush, killing three officers and wounding three others before he was shot to death.

The city of about 229,000 is about 55 percent black and 40 percent white.

Gleason didn’t appear to have any active social media profiles. A spokesman at Louisiana State University said a student by that name attended the university from the fall of 2013 to the fall of 2014 before withdrawing. He had transferred to LSU from Baton Rouge Community College.

During the search of Gleason’s home, authorities also found 9 grams of marijuana and vials of human growth hormone, according to a police document.