Authorities in Chicago are looking for a second teen who was allegedly involved in the sexual assault of a 15-year-old girl that was streamed live on Facebook.
Police issued an arrest warrant for a 15-year-old boy on Sunday.
Authorities charged a 14-year-old boy in the attack Saturday.
About 40 people viewed the assault live- none of them reported it to police.
Officials said multiple videos of the attack have also been made.
Authorities said they expect to file more charges since about 6 people were involved in the attack.