The 15-year-old boy who police say pulled the trigger in the killing of an Overbrook man turned himself in early Friday, accompanied by his father.

Tyfine Hamilton has been charged with murder, robbery, and related offenses in the botched robbery that killed Jim Stuhlman, 51, while walking his dog last week on the 6400 block of Woodcrest Avenue.

Brandon Smith, 15, and a third boy, 14, who was with them were arrested this week. Smith will be charged with murder; the 14-year-old faces lesser charges.

All three are talking to police, a law enforcement source said Friday.

Police said the boys left a basketball game on the night of March 12 looking to rob someone. Hamilton carried the gun. The source said it was unclear how the gun came into the possession of a 15-year-old. The boys set their sights on one man walking a dog, but switched their attention to Stuhlman, police said, because he seemed older and his dog seemed weak.

Still, he was significantly taller than the boys, and Hamilton had to point the gun upward, into Stuhlman's face, the source said.

A brief struggle ensued. Stuhlman pleaded for his life but was shot once in the chest. Panicking, the boys ran. Stuhlman's dog, a Labradoodle named Molly, stayed with him until he was found on the sidewalk. He was pronounced dead a short while later.

Smith and Hamilton are also being investigated for several other robberies in Southwest Philadelphia, the source said.

Smith was arrested Thursday after 19th District officers saw him and the 14-year-old on a street corner and recognized them as matching the description of Stuhlman's attackers.

They darted into a house when they saw police, but were captured soon afterward.

Hamilton's aunt on Friday apologized to Stuhlman's family. Speaking to a CBS3 reporter, she said Hamilton was not taking medication for an unspecified condition.

Hamilton, police said, has been arrested twice as a juvenile, for narcotics and criminal mischief.