Police in Suffolk County discovered skeletal remains in a coastal marsh on Sunday — and homicide detectives are now investigating the find, authorities said. 

Cops found the remains in Mastic Beach Sunday afternoon after a cleaning crew spotted them and called 911 at about 1:35 p.m., according to police. 

The remains were taken to the Suffolk County Medical Examiner for an autopsy, cops said. 

A cause of death and the identity of the person was not immediately known. 

Members of the Suffolk County detective squad are investigating the remains, cops said.