DENVER (KDVR) — Law enforcement sources told the Problem Solvers that Wednesday’s unfounded threat calls to numerous Colorado schools may have originated overseas.

The FBI is looking into all leads after at least 17 schools were targeted by the callers, who reported active shootings on campuses or other threats of violence. The flurry of calls had schools statewide in various states of heightened security.

“Many of these calls are coming from the same number, a TextNow number,” said the Colorado Information Analysis Center, within the state Department of Public Safety.

TextNow is an internet-based calling and texting service.

‘Swatting’ calls hit Colorado schools statewide

Law enforcement officials dub the activity “swatting” — when someone makes a hoax report of a serious crime, like a shooting or bomb threat.

Most of the calls were in the morning, starting just before 8:30 a.m. and continuing every few minutes until 9:45 a.m. Another string of calls went out after 1:30 p.m.

That includes Littleton High School, which still had police officers on campus Wednesday afternoon as they worked to clear a call at the school.

Other affected schools on the Front Range include Aurora Central, Boulder and Brighton high schools and Englewood middle and high schools. Other schools from all over the state were impacted too, from Estes Park to Glenwood Springs to Ouray to Alamosa.

Schools were not the only ones — also targeted was Denver 911 with a call about an FBI Denver office.

Colorado has a nearly 4-year-old law that punishes people caught swatting.

That law took effect in mid-2018. Sen. Jeff Bridges, who sponsored the bill, compared the penalties to that of third-degree assault. If someone is hurt, penalties are more severe.

But legal experts say catching the bad actors is a challenge.