EDINBURG – A criminal justice professor whose classes focus on terrorism said ISIS targets potential recruits all through the web.

CHANNEL 5 NEWS reached out to Philip Etheridge, a University of Texas Rio Grande Valley professor whose classes focus on terrorism.

In his research, he said terrorist groups like ISIS are using social media not just to recruit, but to convince people to carry out attacks for them anywhere. He said they're attacks which can be hard to prevent. 

"This idea that we know what a terrorist looks like, those days are over,” he said. 

Etheridge said lately these groups are focusing more on this tactic, "We've seen this around in Europe, we've seen this in Paris, in France. We've seen this in other countries and now it's in the United States."

CHANNEL 5 NEWS spoke with a mother of three who said just the thought of a terrorist trying to target her kids on social media can be unsettling.

"They're always on Snapchat, on Instagram, Facebook. Those are just the few that I know about," said Crystal Seawell.

Etheridge said parents like Seawell should not worry too much as these groups don't just target anyone.

He said they usually wait for them to make the first move.

"They use methods that find out if somebody is surfing certain pages and may actually start to target people," said Etheridge.

From there he said they'll do what they can to convince them to do these heinous acts.

"The ideology would be I need to do something, you read the literature you may watch some of the stuff terrorists have put out on the web, sermons almost, and you begin to think that way that you need to do something," said Etheridge.

One important factor Etheridge said they look for is someone with a clean record, making them unlikely to suspect.

The FBI said the best way to stop attacks like the one in New York City is to report any suspicious behavior to their website.