By Todd Quinones

PHILADELPHIA (CBS) — Police are investigating a possible sexual assault of a young teenager in an alleyway behind homes in Northeast Philadelphia.

Authorities say a 13-year-old reports being assaulted by two males in the 1400 block of Fanshawe St. The attack happened at about 3:30 p.m.

A witness to the act, who spoke with Eyewitness News, says she saw the young girl preforming a sex act on the two males and it did not appear that she was forced or calling for help.

The witness also said that the young girl ran away in the same direction as the two males, and it wasn’t until she was stopped that the teenager reported being forced.

No arrests have been made.

Further details were not immediately available and an investigation is ongoing.