PITTSBURGH -- Police were called to Montezuma Street in the Lincoln-Lemington neighborhood of Pittsburgh for a report of a sexual assault.

The incident occurred at 8:30 p.m. Friday when a witness reported seeing two juveniles engaging in sexual activity in an alleyway.

Police said the witness approached the pair and a teenage male ran from the area. Officers later tracked down the 15-year-old and took him into custody.

An 11-year-old girl was taken from the scene and transported to Children's Hospital to undergo tests.

After interviewing the teenager, police have charged him with rape of a child because the female involved is under the age of 12.