Investigators say someone shot the man at 9:18 Sunday night at the Sunoco gas station on the corner of Robinson Lane and Maryland Avenue.
When officers arrived they found the victim lying in the snow on a sidewalk.
He was taken to the hospital where he was pronounced dead.
Police identified him as 21-year-old David Johnson.
Detectives are seeking assistance in identifying the three people pictured above, who are now of interest in this incident. To offer information regarding this investigation, please contact the New Castle County Police Department at 302-395-8110.