The killings of two black men in the US state of Louisiana last week were probably racially motivated, police said, and a 23-year-old white man is in custody.
In both shootings the gunman fired from his car then walked up to the victims as they were lying on the ground and fired again multiple times.
The suspect, Kenneth Gleason, was being held on drug charges and was given a 3,500 US dollars bond on Sunday evening, lawyers said.
There was not immediately enough evidence to arrest him on charges related to the killings in Baton Rouge, but the investigation was ongoing, the city's Sergeant L'Jean McKneely said.
Gleason was still behind bars, according to the sheriff's office.
"The victims were ... ambushed," Mr McKneely said.
"There is a strong possibility that it could be racially motivated."
Mr McKneely said shell casings from the shootings linked the two killings, and a car belonging to Gleason fits the description of the vehicle used in the killings.
Neither victim had any prior relationship with Gleason.
The shootings happened about five miles from each other.
The first occurred on Tuesday night when 59-year-old Bruce Cofield, who was homeless, was shot to death.
The second happened on 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, Mr McKneely said.
Mr Smart's aunt, Mary Smart, said she was still dealing with the shock of her nephew's death.
"I'm feeling down and depressed.
"My nephew, I love him, and he was on his way to work and that makes it so sad," she said in a telephone interview.
"He was always smiling and hugging everybody. A lot of people knew him."
Mr Smart had a son and two daughters, she said.
She declined to comment on police allegations that her nephew might have been shot because of the colour of his skin.
"I cannot say," she said. "Only God knows."
No one answered the door at Gleason's house in a quiet neighbourhood of mostly ranch-style homes with well-kept lawns, located about 10 miles from the sites of the shootings.
"He looks like any clean-cut American kid," said neighbour Nancy Reynolds, who said she did not know Gleason or his family.
She said it was "hard to believe this sort of thing is still happening".
Two of Gleason's cousins said they could not believe he had anything to do with the killings.
"He had no problems with any person," said Garrett Sing, 37.
"He had black friends, white friends, Asian friends. He made friends with anyone."
Another cousin, 33-year-old Barton Sing, described Gleason as a "good kid" and recalled how his cousin recently asked him to teach him how to bow hunt.
"He said he never liked guns. That's why he wanted to get into archery," Mr Sing said.
"He's the last person I'd think to do something like this."