A 14-year-old boy has been arrested in connection with the sexual assault last month of a 15-year-old Chicago girl that was livestreamed on Facebook Live.

The unidentified suspect faces felony charges of aggravated criminal sexual assault, manufacturing of child pornography and dissemination of child pornography, police said Sunday during a news conference. More arrests are expected in connection with the attack, which was viewed as it happened by about 40 people, none of whom reported it to police.

"It disgusts me. It makes you wonder, what are we doing as a society, that people watch this and don't pick up the phone and alert police," Chicago Police Superintendent Eddie Johnson said Sunday.

Facebook Live, which lets anyone with a phone and internet connection livestream video directly to Facebook's 1.8 billion users, has become a centerpiece feature for the social network. In the past few months, everyone from Hamilton cast members to the Donald Trump campaign have turned to Facebook to broadcast in real time.

But the focus on video has prompted some tough philosophical questions, like what Facebook should and shouldn't show. In the year since its launch, the feature has been used to broadcast at least 50 acts of violence, according to the Wall Street Journal, including murder and suicides.

The sexual assault victim has also been the target of social media bullying, police said.

The mid-March assault marked the second time in recent months Chicago police have investigated an apparent attack streamed on Facebook Live. In January, four people were arrested in the beating of a special-needs teenager that was livestreamed on the tool.

Police said Facebook assisted them in securing search warrants that led to the charges. Another warrant has been issued for the arrest of another minor suspect, police said.

Facebook did not immediately respond to a request for comment.

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