Paramedics were dispatched at 7:53 a.m. Monday after a passerby found the body in the 2100 block of Delaview Avenue.
That man, 43-year-old Wayne Cappelli of Claymont, died from blunt force trauma to the upper body, police said.
Investigators believe he was attacked on Saturday night at or near that location, and also said a vehicle may have been involved.
Police do not have any suspects in this case.
Anyone with information is asked to contact New Castle County Police Detectives at 302-395-8110 or call the non-emergency dispatch number 302-573-2800.