Police today released a composite of a teenage boy who they say sexually assaulted a 17-year-old girl as she ran along the Sawmill Branch Walk/Bike Trail in Summerville.

The assault happened about 1:30 p.m. on Wednesday, according to an incident report. The girl told police a teenage boy on a bicycle smacked her on her buttocks as she ran along the trail.

She became upset, the report states, but she continued to run.

The boy reappeared, she told police, this time ramming his bicycle into her.

Then, the boy jumped off the bike, pulled out a silver pocket knife and told the girl to shut up, the incident report states.

The girl told police her attacker punched her in her face three times.

She told him she would do anything he asked, so long as he let her live, the report states.

The boy pulled the girl into the woods and pushed her down on her back. According to the report he held the knife up to her throat while he sexually assaulted her.

A man walked by the edge of the woods and asked if there was a problem, interrupting the attack, the report states.

The boy told the man he was attempting to have sex with his girlfriend, according to the report. The girl, however, cried out for help, prompting her attacker to run out of the woods and flee on his bike.

The girl ran toward her car, which was parked at the trailís entrance on Bacons Bridge Road, the report states.

She drove home and told her father, who called police.

A witnesses reported seeing the girl crying hysterically and yelling for help. That person told police the girl didnít have on pants and was red in the face.

The girl described her attacker as being white, about 17 years old, having curly brown hair and wearing a camouflage jacket and blue jeans.

She told police she runs the trail often, but she didnít recognize him.

Anyone with information can call Crime Stoppers at 554-1111.