After a series of shots, some of them fatal, at homeless men in Washington and New York, investigators in the US capital arrested a suspect.
The man is currently being questioned, Washington police said on Twitter on Tuesday morning.
He is suspected of having been shooting at homeless people on the streets of both cities since the beginning of March.
Two of his victims were killed, three more survived.
A large-scale manhunt for the suspected shooter, who had been recorded by several surveillance cameras, has been underway since Monday.
They showed a slim, rather younger man with a beard and a bald head.
In a joint statement, New York and Washington Mayors Eric Adams and Muriel Bowser warned of a "ruthless killer" roaming the streets of both cities.
"Cold-blooded" marksman
According to the investigators, the shooter acted "in cold blood" and always followed the same pattern.
His first victims were attacked on March 3rd and 8th in the northeast of the capital, they survived.
A day later, helpers discovered the body of a homeless man in a burning tent in Washington.
According to the autopsy, she had multiple gunshot and stab wounds.
In New York, 400 kilometers away, a homeless man was shot in Lower Manhattan in New York last Saturday.
About half an hour later, police in the same neighborhood found the body of another man in his sleeping bag.
He was killed with shots in the head and neck.
Surveillance camera footage of the murder eventually led police to the suspected serial killer.