One of the boys who allegedly participated in the gang rape of a Chicago teen during a live broadcast on Facebook last month was arrested over the weekend. The 14-year-old has been charged with felony counts of aggravated criminal sexual assault, manufacturing of child pornography, and dissemination of child pornography. Police say they expect more arrests to come, including that of the person who recorded the incident.

The girl, a high school freshman, was reported missing on March 19 and found two days later near her home. According to police, the 15-year-old was "lured" to a residence by someone she knew, where she was sexually assaulted by as many as six males. The next day, her family approached police at a news conference and told them they'd witnessed the girl being attacked by several boys in a video streamed on Facebook Live. They presented screenshots of the video as proof.

Police suspect upwards of 40 people viewed the video documenting the girl's horrific attack; however, no one alerted authorities.

Since the girl was reunited with her family, she continues to be harassed, police say. "She's just having such a difficult time even communicating what occurred to her," Cmdr. Brendan Deenihan said at a news conference on Sunday. "We obviously have a video of the incident, so we have verifiable objective evidence of what occurred to this young lady, but she's just having a very difficult time. On top of it, there's constant social media ... bullying (of the girl), making fun of what occurred."

It's not the first time social media users have witnessed a horrendous crime occur via Facebook Live—including in Chicago. In January, four people were charged with a hate crime for kidnapping and torturing a disabled man in Chicago, which they allegedly streamed online. The video had reportedly been viewed more than 62,000 times before it was removed.

"The way in which the narrative usually goes in the aftermath of these events is that Americans are callous, Americans don't care, Americans don't want to get involved," Arthur Lurigio, a psychology professor at Loyola University Chicago, told the Chicago Tribune last year. "That's people's initial reaction: outrage. How can you watch when someone is being victimized?"

But Lurigio suggested the lack of action may be in part due to uncertainty. "There's some degree of ambiguity with regard to the moral or social imperative of these situations, and there's also an element of self-protection."

According to a study published last month in the Journal of Interpersonal Violence, only a third of respondents reported intervening as a bystander in cases of sexual assault. "This means that either a large part of the population does not perceive such instances as emergencies, perhaps because they occurred in the distant past or the victim is not in imminent danger, or the barriers to intervening outweigh the benefits, even when an incident is perceived to be an emergency," the study states.

"Moreover," says Abigail Weitzman, a research fellow at the University of Michigan's Population Studies Center and one of the authors on the study, "the average individual is somewhere between five and 10 times more likely to intervene on behalf of someone they know closely (a family member, friend, or acquaintance) than on behalf of someone else. In practice, this means that very few people intervene in instances of sexual assault when they don't know the victim well or at all."

Weitzman offers a number of reasons why people hesitate to intervene. "One of the biggest issues continues to be rape myths, e.g., beliefs (whether subconscious or not) that individuals who are assaulted, especially women, want or 'ask for' assault by behaving a certain way," she explains to Broadly. "These beliefs can contribute to uncertainty or confusion when witnessing or hearing about a specific incident. Another big issue is a lack of awareness on how to intervene: Many people don't know what to do or don't feel it is their place to do anything because they view victimization as a personal and private matter." Other deterrents, she continues, include systemic police discrimination against select communities and the lack of cultural support for those who step in.