PENN HILLS, Pa. (KDKA) – The FBI believes a Penn Hills man may have used Snapchat to prey on young girls across the nation.

Kaung Myat Kyaw, 22, was indicted by a federal grand jury on child exploitation charges, prosecutors announced Wednesday.

He’s accused of getting the victims’ nude photos either by phishing for their Snapchat information or catfishing, the FBI said.

“He’s been sending phishing emails to a number of underage victims representing himself as technical support from Snapchat and through those phishing emails he’s gained access to their private accounts and private photos,” said Joe Rothrock, the special agent in charge of the investigation.

He would then start the “7 day challenge” where the FBI said he made the victims produce increasingly demeaning photos and videos for the next seven days, threatening to send their photos to family and friends if they didn’t participate.

READ MORE: FBI Accuses Penn Hills Man Of Preying On Teens Via Snapchat

Prosecutors said he exploited four minors, but the FBI believes there could be more across the nation. They’re already investigating with law enforcement in Phoenix, Buffalo and Virginia.

FBI agents said he used multiple cell phones and a laptop to sexually exploit children. In one week’s time, Rothrock said Kyaw tried to sextort at least ten different girls on Snapchat.

“It’s really difficult for us as the FBI to determine how many victims there are unless the public comes forward and we know that in these types of investigations, it’s extremely difficult for the victims to report it to law enforcement,” Rothrock said.

His victims might have known him as savnxh, jokerxkris, krxs.com, the FBI said. Anyone who with information is asked to contact the FBI.

The FBI wants parents to talk to their kids and make sure they know these people are out there and they are trying to encounter children online. One of the biggest red flags: they’ll often meet the child and start talking on one social media platform and then try to move the conversation to a second platform for a more discreet conversation.

Meghan Schiller