Boston police are investigating the fatal shooting of a 19-year-old man in Dorchester early Wednesday.

The victim, who was found shot in the head about 1:30 a.m in the 700 block of Washington Street near Dunbar Avenue, was pronounced dead at the scene, according to Boston Police spokesman Lieutenant Detective Michael McCarthy. A law enforcement official briefed on the case said the “victim was clearly targeted,’’ though officials said they are still trying to determine a motive.

Two people familiar with the investigation identified the slain man as Alvin Sealey.

A woman who identified herself as Sealey’s mother declined to comment Wednesday.

“He was a fun kid,’’ said Jesse Librot, 33, who worked at Camp Mitton with Crossroads for Kids program, which Sealey attended for several years until the age of 14. “He was very energetic. The kind of kid we love in camp.’’

Librot said that Sealey had recently messaged him on Facebook to share that he had graduated from high school. Librot said Sealey also planned to return to the camp to work and had helped younger children at the camp before.

Crossroads for Kids is a residential camp for “under-resourced youth,’’ according to the program’s website.

On Wednesday, Librot and others took to Facebook to share their memories of Sealey.

“Handed so many challenges not by choice, Alvin always worked hard and overcame them,’’ Librot wrote.