OAKLAND — U.S. attorneys have filed criminal charges against an East Bay man who they say made hundreds of threatening or harassing phone calls to police departments around the country, including allegedly describing sexual acts to a Canadian mountie.

Sammy Sultan, of Hayward, faces five years in prison if convicted of making obscene or harassing calls and violations of interstate communications. The affidavit in support of his arrest tells the story of extreme crank calls made from February 2015 to August 2016. They included death threats, fake hostage calls, and a request to sniff a Massachusetts’s dispatcher’s slipper.

Many of the calls fit the same pattern: The caller would say he’d recently escaped a mental institution, had weapons in his possession, and that he wouldn’t hurt anyone if the dispatcher listened to him, according to the affidavit. Calls were made to hundreds of police departments, in at least 18 states.

Authorities linked the calls to five Metro PCS cell phones allegedly owned by Sultan, and asked Hayward police to send officers to his home.

During a June 2015 conversation with police, Sultan said, “This is like the fifth time this crap happened,” and later mentioned police had been to his home before to investigate someone being held against their will.

Sultan denied being responsible for a disturbance, and remarked that the situation was “ridiculous,” according to the affidavit.

Federal investigators reviewed an officer’s body camera footage of the exchange and determined Sultan’s voice was similar to that of the serial caller. Still the phone calls to police departments continued.

Then, in 2016, a wave of similar calls struck Canada. After the Royal Canadian Mounted Police received a call in April — in which the caller made references to the dispatcher’s feet and described committing sexual acts — Hayward police were asked to interview Sultan a second time. They showed up at his home again, and he denied having a working computer or cell phone, according to the affidavit.

Months later, authorities served a search warrant on Sultan’s home. They found he’d been researching police dispatch centers — including pictures of female police dispatchers — and found a recording of a woman in distress that authorities believe Sultan used to help simulate a hostage situation during the calls.

Sultan has been released on $5,000 bond, on the condition he not make calls to police agencies except for emergencies, according to court records.