JACKSONVILLE, Fla. -

A 17-year-old was arrested Monday morning in the killing of an 18-year-old man earlier this month.

Gregory Robinson is charged with murder in the death of Adrian Watkins Jr.

Watkins' body was found in a ditch near Beverly Hills Park on Feb. 1.

Both teens had been friends for years and both formerly attended First Coast High School.

Adrian Watkins Jr.

Jacksonville police said there was a fight at the school last month. They said Robinson and Watkins were expelled and both enrolled at an alternative school.

Police said the fight wasn't just between those two; others were involved.

They said the teens wound up at the park and there was a confrontation for reasons unknown. Police said Robinson shot and killed Watkins.

Police said they found the handgun believed used in the killing hidden in the attic of Robinson's house.

Channel 4 spoke with Watkins' parents, who were stunned by the arrest. They said they thought Robinson was their son's friend.

"I didn't suspect that he did it because they was friends. You don't look to your friends to do something as heinous as this," said Adrian Watkins Sr.

The Watkins family told Channel 4 that Robinson lived across the street and had told them to their face he was not responsible for Watkins' murder.

"Looked me in the face and said he didn't know anything about what happened. It hurts but I have to forgive him and move on, because if I don't it's gonna hurt me more," said Watkins.

"I can't believe that he was at our house, said he was my son's friend and looked us in the face and came over and checked on us twice. Can't believe my son died for nothing," said Genea Watkins.

The Watkins family said the friends had some sort of argument over Robinson, which led to Robinson getting in trouble at school.

"He told on him at school. That's what they said -- he told on him. That's why he threw him in a ditch," said Adrian Watkins Sr. "These kids today, they have this thing, if you snitch you're in a ditch. To me, it's sickening."