A copy of an Adolf Hitler speech has been found at the home of a 23-year-old white suspect accused of killing two black men and firing on a family, in a string of attacks that police say may have been racially motivated.

A law enforcement official said the Hitler speech was found at the home of Kenneth Gleason in Baton Rouge, Louisiana, and investigators said DNA on shell casings and other evidence linked him to the crimes.

Gleason was led away in handcuffs on Tuesday, just before authorities held a news conference to announce that he would be charged with first-degree murder over the fatal shootings last week of a homeless man and a dishwasher who was walking to work.

(AP)
(AP)

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

Gleason’s lawyer, Christopher Alexander, said his client “vehemently denies guilt, and we look forward to complete vindication”.

Authorities found a copy of the Hitler speech during a search of Gleason’s home over the weekend, according to the law enforcement source.

Asked whether police suspected race was a motive for the shootings, Sergeant 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.”

East Baton Rouge Parish district attorney Hillar C Moore III. (AP)
East Baton Rouge Parish district attorney Hillar C Moore III. (AP)

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 neighbourhood on September 11, authorities said.

It is 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 several times, police said. Neither victim had any prior relationship with Gleason.

Baton Rouge Mayor Sharon Weston Broome. (AP)
Baton Rouge Mayor Sharon Weston Broome. (AP)

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

The attacks came at a time when Louisiana’s capital already was in the grip of a surge in violence.

The number of murders in East Baton Rouge Parish has already surpassed last year’s total of 62, The Advocate newspaper said 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 rocked the city in the summer of 2016 when a black man was shot dead by white police officers outside a convenience store.

(AP)
(AP)

About two weeks later, a black gunman targeted police in an ambush, killing three officers and wounding three others before he was shot dead.

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

Gleason did not appear to have any active social media profiles.

A spokesman at Louisiana State University said a student by that name attended the university from autumn 2013 to autumn 2014 before withdrawing. He had transferred to LSU from Baton Rouge Community College.

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