A bicyclist was killed Thursday in a crash with a semi-truck in South Tucson.

The man, 60-year-old Robert Lucke of Oro Valley, was pronounced dead at the scene at South Sixth Avenue and East 36th Street, said Det. Sgt. Bryce Gardner, a South Tucson Police Department spokesman.

Shortly before noon, officers responded to the crash and the semi-truck driver remained at the scene and cooperated with detectives, Gardner said.

Investigators learned Lucke and the semi-truck were traveling north on South Sixth Avenue in the curb lane. As the truck was turning east on 36th Street, the bicyclist collided with the truck, said Gardner.

The cause of the crash remains under investigation. South Tucson Police were assisted by Arizona Department of Public Safety and Tohono O'odham Police Department traffic investigators.

Contact reporter Carmen Duarte at cduarte@tucson.com or 573-4104. On Twitter: @cduartestar