University of Maryland Police received four reports of scams over the past two weeks, according to a UMD Alert sent Friday. In each case, the victims were associated with the university and were contacted either by phone or email.

The callers pretended to be from a government agency, employer, electric company or immigration-related law enforcement, according to the alert. The scammers falsely accused victims and used fear tactics to urge victims to buy gift cards or bitcoin to avoid further action against them.

The alert offered advice for community members on how to avoid falling victim to a scam. Scammers may call, email, text or approach victims in person, according to the alert, and they’ll often remain on the line until victims comply with demands.