Police were investigating a fatal confrontation in Mattapan on Sunday after one man was found dead and another badly injured on River Street.

Officers responded around 2 a.m. to the area of 227 River Street, near the Mattapan Heights apartment building and Transitions Treatment Program, according to a police report.

RELATED: Man sentenced to 10-12 years for machete attack

There, they found one man in his 20s suffering from gunshot wounds. He was pronounced dead at the scene, the report said.

First-responders transferred a second man, who is also in his 20s, to a nearby hospital with a stab wound described as non-life threatening.

RELATED: Child porn investigation leads to after-school teacher

Police are now looking for the public’s help, asking anyone with information to contact BPD detectives at 617-343-4470 or leave an anonymous tip at 1-800-494-TIPS or via text to CRIME (27463).