A 15-year-old girl seized on the national scary clown craze and posted on Facebook a violent threat to residents of many Twin Cities communities, and police in one of those cities said they have arrested the juvenile.

"Kroacky Klown has been identified and charges will be pursued for their threats," Hopkins police said in its own notice late Tuesday on Facebook.

Police Sgt. Mike Glassberg said his department received information via Facebook that Kroacky Klown posted: "Should I come to Hopkins and kill?"

The girl was tracked down and identified as being from Bloomington, Glassberg said. Police were withholding her identity because she is a juvenile.

"The suspect had used her younger sister's cellphone to create the fictitious Facebook account," the sergeant said. "The juvenile told police her intent was to scare her boyfriend, but the situation got out of control and went viral."

Glassberg said that another Kroacky Klown threat on Facebook by the girl read: "If you live in the following Minnesota cities you are in danger: Bloomington, Richfield, Minneapolis, Brooklyn Park, St. Paul, Rochester, Apple Valley, Plymouth or HOPKINS. My clown brothers are in every city listed."

The Kroacky Klown photo depicted the character behind jail bars with a sinister sneer and a bloody gash over one eye.

In St. Paul, the school district issued a notice on Twitter and Facebook about it receiving "reports of several threatening 'creepy clown' messages on social media, as well as sightings of clowns in St. Paul."

The district added that even though "these situations are believed to be hoaxes," its security staff is "monitoring reports and will work closely with St. Paul Police to ensure the safety of our students."

St. Paul Police Sgt. Mike Ernster said Wednesday that his department and school officials are working "to ensure our students have a safe and secure learning environment. … We have not had any reported sightings."

Glassberg urged parents to "remind their children about the consequences of inappropriate behavior on social media, which may become criminal in nature."

The Police Department in Hopkins takes these threats seriously, Glassberg continued, "and does not clown around."

In Farmington, the police chief expressed exasperation this week with all the hubbub on the internet and elsewhere about scary clowns.

"I received a call from a very upset parent," said Brian Lindquist, chief of the south metro suburb. "He identified his child as the party responsible for Bobo the friendly clown. There was no malicious intent, there was no ill will; it was merely an attempt to scare their best friend."

Noting that he's seen "the great benefits and the awful dangers of social media," Lindquist urged everyone "to take two seconds before you hit the send key. … We are done with Bobo the Clown. He doesn't exist. Stay safe and be kind to your neighbors."

People in Alabama, Georgia, Maryland, North Carolina and Pennsylvania have reported scary or suspicious encounters with people dressed as clowns.

"When people report these things it should be 'someone dressed like a clown,' because a real clown would never dress or do anything to scare anyone," said Tricia Manuel, 55, who runs Mooseburger Clown Arts Camp in Maple Lake, Minn. The camp, named for her alter ego, Pricilla Mooseburger, trains about 100 clowns each year.

She has watched the numerous reports closely because she says they are hurting business.

"In South Carolina, two of the clowns were afraid to go out and perform, and they're two of my customers," said Manuel, whose two children are also clowns.

Author Stephen King has made a fortune scaring people and one of his creepiest books was "It," featuring a monster in the form of a clown. King spoke out Monday as a voice of pro-clown reason.

"Hey, guys, time to cool the clown hysteria," King tweeted Monday, "most of em are good, cheer up the kiddies, make people laugh."

The Associated Press and the Washington Post contributed to this report. Paul Walsh • 612-673-4482