(WLUK) — A Green Bay man learned his sentence for making threatening and obscene phone calls to daycare centers in other states.

Michael Propst, 46, was sentenced to seven years in federal prison, two and a half times longer than the recommended federal sentencing guidelines.

According to court documents, Propst called two different daycare centers in Indiana, claiming he was raping and harming one of their pupils.

Panicked daycare workers quickly did a head-count of their children and called authorities.

When those at the Green Bay office of the FBI became involved, they learned a federal investigation was underway into Propst in Delaware. Investigators say Propst was linked to similar threatening calls in fifteen other states, from Maine to California.

Over the span of 20 years, prosecutors say Propst made threatening phone calls to schools, daycare centers and retail establishments, depicting the violent rape of young children.

Prosecutors say Propst’s job as a long-haul trucker made it practically impossible for local authorities to investigate his threatening calls, given he and his phone were constantly moving through different legal jurisdictions.

Propst was previously convicted in the state of Florida in 1999 for making similar obscene and threatening phone calls. In 2002, he was sentenced to 41 months in prison. Prosecutors say the calls only stopped while Propst was incarcerated.

During his sentencing, the judge described Propst’s actions far more serious than just harassment, calling it akin to “terrorism.”

Following his current prison sentence, Propst is ordered to serve three years of supervised release.