ST. LOUIS, Missouri - August 29, 2011 - There’s an alert out about recent assaults on bike riders in south St. Louis.

Trailnet.org, an organization that promotes hiking and biking, is cautioning riders to be on the alert for roving bands of teenagers who swarm and attack riders.

Trailnet says the latest attack was last Thursday afternoon near Missouri Botanical Garden, where a group of 10 to 15 black teens charged and attacked a cyclist.

“They weren’t really interested in robbing me. It just seemed like they wanted to beat me up,” says assault victim Cheech Ramirez. “They weren’t interested in letting me get off the ground and having a fair fight.”

Ramirez says he and his friends returned to the scene minutes later to help another bicyclist who was being beaten.

Police say there have been other similar attacks in the city, and they believe all the victims are picked at random.

Mayor Francis Slay is calling for action, possibly with citizen bike patrols set up with the help of Trailnet and local police.

Police urge bike riders to be aware of their surroundings and call 911 when they see a swarm mob preparing for an assault.