Aamer Madhani

USA TODAY

CHICAGO — Police on Tuesday said they are searching for five to six men suspected of sexually assaulting a 15-year-old girl in an attack that was streamed on Facebook Live.

The girl, who had been missing since Sunday, was found by Chicago detectives Tuesday — the day after the girl’s mother approached Superintendent Eddie Johnson as he was leaving a news conference and showed him screen grabs of the attack, according to police.

The video, which has been removed from Facebook, was viewed by dozens of people, but no one called authorities.

“The superintendent was visibly upset when he saw the pictures of the girl and was dismayed when he learned that people were watching the incident live and no one called police,” police spokesman Anthony Guglielmi said.

Facebook declined to respond to specific questions about the incident, including whether the alleged assault was flagged by any Facebook users. The company says it reviews questionable content around the clock that is reported by users and has systems in place to ensure that time sensitive content is dealt with quickly.

“Crimes like this are hideous and we do not allow that kind of content on Facebook," the company said in a statement. "We take our responsibility to keep people safe on Facebook very seriously and will remove videos that depict sexual assault and are shared to glorify violence.”

Guglielmi said that investigators were "making good progress identifying persons of interest" in the assault.

With the emergence of Facebook Live as well as Twitter’s live-streaming platform Periscope, it’s become more common for violent incidents to be streamed to the world in real-time.

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Last month, an Ohio woman was sentenced to nine months in prison after pleading guilty to obstructing justice for livestreaming a 29-year-old man raping a 17-year-old girl on Periscope. Marina Lonina, 19, had initially faced more serious charges of rape and pandering sexual matter involving a minor. The man charged with the assault, Raymond Gates, also pleaded guilty and was sentenced to nine years in prison.

In January, four young African-American suspects in Chicago were charged for the alleged torture and beating of a white teen with mental health challenges that was broadcast on Facebook Live. Prosecutors pointed to evidence from the livestream to make the case that the boy, who suffers from schizophrenia, was the victim of a hate crime.

Facebook Live footage is expected to be used in the prosecution of a Minnesota police officer charged with second-degree manslaughter and two counts of dangerous discharge of a firearm for the high-profile shooting death of a motorist, Philando Castile. The aftermath of the controversial shooting was streamed by Castile's girlfriend, Diamond Reynolds, who along with her daughter were passengers in the vehicle. The trial of the officer, Jeronimo Yanez, is tentatively scheduled to begin May 30.

Read More:

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Follow USA TODAY Chicago correspondent Aamer Madhani on Twitter: @AamerISmad