FAYETTEVILLE, Tenn. (AP) _ Jacob Davis was supposed to graduate this week in the top 20 of his senior class. Instead, he is in jail, charged with killing a classmate who was dating his ex-girlfriend.

According to his father, Davis, 18, had never been in trouble at school and had college scholarship offers awaiting him.

Lincoln County High School, where he was one of about 300 seniors, was open today and a prayer vigil was planned. Graduation still is scheduled for Friday.

It was in the school parking lot that Robert ``Nick'' Creson, an 18-year-old member of the school's football team, was fatally shot Tuesday.

``Apparently Jacob was despondent that Mr. Creson was dating his girlfriend,'' police investigator Bill Wood said.

Police said Davis left school about noon after arguing with Creson over ex-girlfriend Tonya Bishop, another senior. They believe Davis went home and got a .22-caliber rifle, then returned to the school parking lot to wait for Creson.

When Creson walked up shortly after 2 p.m., police said Davis got out of his car and shot at him once from 15 to 20 feet away. It's unclear whether it struck Creson.

``Nick told him, `Quit messing around,''' police Chief Tom Barnes said. ``The second shot hit him somewhere in the chest and he fell backwards and there was another shot fired into Nick as he was on the ground.''

Creson, wounded in the chest and abdomen, died a short time later at a hospital.

The dozen or so students who witnessed the shooting said Davis never uttered a word, Wood said.

He did, however, leave a two-page letter in his car ``telling his mother and father how much he appreciated them, and telling his girlfriend how much he loved her,'' Wood said. ``He was basically asking forgiveness for what he was about to do.''

Police also found several photographs of Davis and the girl in his car, Wood said.

After the shooting, witnesses said Davis placed the rifle on the pavement and sat with his head in his hands until police came. He surrendered without incident.

Barnes said Davis didn't say anything to police, except that he wanted to talk to his parents and his lawyer. As to why the dispute with Creson turned deadly, Barnes said: ``Only Jacob knows and Jacob's not talking.''

Fayetteville is about 80 miles south of Nashville near the Alabama state line.

It was at least the fourth fatal shooting at a Southern school since Oct. 1, when a 16-year-old student in Pearl, Miss., killed his mother, then went to school and shot nine students. Two of them died.

Six weeks ago, an 11-year-old boy and his 13-year-old friend opened fire on classmates in Jonesboro, Ark. Four pupils and a teacher were killed and 10 people wounded.