State Police detectives assigned to Suffolk County District Attorney Daniel F. Conley’s office have identified the man found dead near the Charles River Esplanade early this morning.

Using a post office box number handwritten on a scrap of paper found in the man’s pocket, detectives were able to identify the deceased late this afternoon as a 54-year-old Upton man. They were then able to contact the man’s sister and inform her of his death.

Firefighters, emergency medical technicians, and police responding to a passerby’s 4:45 a.m. call found the man slumped to his right on a park bench facing the water near the Hatch Memorial Shell. He was pronounced dead at the scene. The cause and manner of his death remain under investigation pending a complete autopsy, but investigators saw no outward signs of trauma or obvious indications of foul play.

The man had no identification or personal papers on him. Efforts to identify him through fingerprints, facial recognition software, and other methods proved fruitless, and Conley’s office was prepared to seek the public’s help in learning his name and locating his next of kin.

State Police assigned to Conley’s office have jurisdiction over all death investigations in Chelsea, Revere, and Winthrop, as well as state roadways, waterways, and property within the City of Boston.