UPDATE: 15-year-old shooting victim dies

Shag Qu-Tee Marshall is charged with attempted murder and remains in custody.

A 15-year-old Colleton County boy died Wednesday of injuries he suffered when he was shot in the head Tuesday morning, authorities said.

Colleton County Sheriff's Office identified the victim as Calvin Fishburne Jr. of Keegan Road. Deputies said a charge of murder will be added to the list of charges against the man accused of killing him, 34-year-old Shag Qu-Tee Marshall of Kershaw.

Calvin's brother, 17-year-old Quinton Simmons, suffered minor injuries when a bullet grazed the back of his neck, according to a family member.

Sheriff's deputies received the call shortly before 9 a.m. and set up a perimeter around a rural mobile home park off Keegan Drive. They used dogs and a helicopter to locate the suspect.

Deputies also found a handgun nearby, according to Chief Deputy Ted Stanfield.

Sheriff's officials said the suspected motive for the shooting involves an ex-girlfriend.

The victims' family knows little about the circumstances, according to their older sibling, 35-year-old Timothy Rivers.

"He just came in there talking about somebody talking to his girlfriend and shot Calvin and my other brother," Rivers said. "He said he would kill both of them, but he didn't have enough bullets."

Marshall remains at the Colleton County Detention Center on charges of murder, attempted murder and possession of a firearm during the commission of a violent crime.

Investigators blocked off Keegan Drive for more than two hours after the shooting. They ringed the boys' home in yellow crime scene tape, and labeled the porch of the white trailer with evidence markers.

Erica Gatewood, who lives next door, said Simmons, the 17-year-old brother, pounded on her door Tuesday shortly before 9 a.m.

"Let me in! Let me in!" he pleaded. When she opened the door, he told her a man had shot his little brother and fled.

Gatewood told Simmons to call 911, but she said he told her he was scared the man would come back. So she called authorities herself, as Simmons ran back to check on Fishburn.

Gatewood said the two boys often came to her home for meals as part of the county's Summer Feeding Program. They talked about school and played with Gatewood's three daughters, ages 3 to 8.

"This makes me afraid for me and my children," she said after the shooting. Gatewood is expecting a fourth child, a son, in about a month.

Before Tuesday, she said, she considered the mobile home park off Keegan Drive a sleepy, safe place to live.