BROOKVILLE, N.Y. (CBSNewYork) — A Long Island University senior has been arrested on federal child pornography charges, just a day before he was set to graduate.

Federal agents alleged that he used aliases and a fake girlfriend to victimize underage minors online.

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Robert Garneau, 21, of Warwick, is accused of posing as a girl on Instagram, the messaging app Kik, and gaming websites and convincing young boys no older than 13 to send him explicit photos and video of themselves, prosecutors said.

Garneau would threaten to tell police unless the boys him sent more explicit images and videos, according to the criminal complaint.

In one incident, the complaint states Garneau allegedly threatened to show the explicit images to the victim’s Instagram followers if he refused to send him more videos.

“Robert Garneau’s alleged crimes are the nightmare of every modern parent,” Manhattan U.S. Attorney Preet Bharara said. “Using every day social media websites, Garneau allegedly exploited minors for his own sexual gratification.”

“As kids spend more and more time on the internet and gaming consoles, parents must step up by teaching their kids how to spot internet predators and talking to them about who they talk to and what information they share,” Homeland Security Special Agent in Charge Angel M. Melendez said.

Garneau was taken into federal custody in his dorm room Thursday morning.

Garneau is charged with three counts of sexual exploitation of a minor. Each charge carries a minimum sentence of 15 years in prison and a maximum sentence of 30 years in prison.

Court records suggest there may be 20 more victims.

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As CBS2’s Bryan Conybeare reported, prosecutors said Garneau went by several names including “Raptorr427,” “Bobby Sixx,” “Allison Denario,” and “Giannafitz81.”

In one case, agents allege that Garneau tricked a California 12-year0old into believing he was sending nude photos to Garneau’s fake girlfriend.

Agents said Garneau would sometimes pressure the victims to send nude photos while traveling from upstate Orange County to his dorm at LIU Post in Brookville.

Investigators found at least 50 explicit images and videos of boys on two cellphones and an iPad given to them by Garneau, according the criminal complaint.

LIU Post officials would not comment calling it a non-campus issue, but fellow students were stunned.

“I think it’s really despicable, and I’m just in shock a little that these types of things are occurring in the area where we are living,” Nicole Ringel said.

Other students called it a cautionary tale.

“Don’t do it, ya know, it’s great the internet, but it’s definitely a double edged sword if you use it the wrong way,” Wilkenson Chery said.

Garneau faces 30 years if convicted.

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Anyone with information is asked to contact Homeland Security Investigations at 1-866-DHS-2-ICE.