Nohemi Gonzalez, a 23-year-old American exchange student, was among the 130 people who died in the terrorist attacks claimed by IS in Paris on November 13. Now her father is suing Facebook, Twitter and Google, the owner of YouTube, claiming the social media websites are complicit in his daughter's death.

A suit filed by the lawyers of Reynaldo Gonzalez in the US District Court for Northern California claims the platforms have provided "material support" to groups like IS, allowing them to carry out attacks like the one in Paris. It goes on to argue that the three companies have for years "knowingly permitted" IS to use their sites as tools for recruitment, financing and propaganda.

"Without defendants Twitter, Facebook and Google (YouTube), the explosive growth of [IS] over the last few years into the most-feared terrorist group in the world would not have been possible," the suit claims.

Twitter and Facebook have dismissed the merits of the case, while Google declined to comment directly on it. All three companies said they actively sought to remove content from their websites that was either deemed threatening or linked to a known terrorist organization.

An ongoing debate

US-based social media companies have come under pressure from governments around the world in recent months after a spate of high-profile attacks linked to IS. Following December's mass shooting in San Bernardino, California, Facebook began aggressively policing extremist content on its website. In February, Twitter announced it had suspended 125,000 accounts "for threatening or promoting terrorist acts."

Still, some argue that social media platforms aren't doing enough to combat the rise of extremism. So how significant a role does social media play in helping groups like IS commit violent acts?

According to David Mair, a PhD candidate at Swansea University in Wales who specializes in terrorists' use of social media, these platforms are more useful to groups like IS after big attacks, not before. Following an event like the mass murder in Paris is when "social media will go into play" in an effort by these groups to promote their actions, Mair told DW. On the other hand, these platforms play only a minimal role in coordinating attacks.

"Social media is more about heightening the effect after the effect," Mair explained.

Is more surveillance necessary?

Facebook, Twitter and YouTube all have their own strategies to weed out extremist content on their platforms, Mair noted. YouTube and Twitter, like other social media sites, utilize flagging programs whereby any user can forward information they think is hate speech. Facebook relies largely on self policing but also reviews and at times deletes flagged content.

Flagging hate speech on social media platforms doesn't necessarily prevent an attack from occurring, according to Mair. As an example, he pointed to the case of Lee Rigby, a British Army soldier murdered on the streets of London by a pair of extremists. One of Rigby's attackers, Michael Adebowale, had been brought to the attention of Facebook for content he'd posted on the site, and at one point the company had shut down his account. However, information about Adebowale was never passed on to British security forces, and Facebook was subsequently criticized for not doing more to prevent the attack.

Mair believes that even had Facebook notified the government about Adebowale, an attack would've likely still happened. He emphasized that terrorists have other secure means besides social media to plot attacks, such as burner phones and encryption. Pressuring social media platforms to increase their surveillance isn't necessarily the way to fight terrorism.

"The knee-jerk reaction is to say let's look at everyone, let's look at the data," Mair said. "The extent to which more evasive monitoring [on social media] works isn't clear."

What's also unclear is how far the Gonzalez family's case against Facebook, Twitter and Google will go. Still, one thing remains certain: The role of social media in modern-day terrorism will continue to be hotly debated.