A 13-year-old Chesterfield Township girl is charged with a felony after Macomb County authorities say she called in bomb threats last week to two middle schools.

Authorities said the teen made the threats as a "copycat" of other threats made at Melvindale-Northern Allen Park schools in Wayne County, which canceled classes for three days last week, according to a news release from Macomb County Prosecutor Eric Smith's Office.

In Macomb County, the suspect said her friend dared her to make the calls and was on the other line when the calls were made Wednesday. The two students were not in school that day because of prior suspensions, according to the news release.

Smith authorized a charge of false bomb threat, a four-year felony, against the suspect. She will be charged in juvenile court, according to his office. It added that the matter involving the suspect's friend remains under investigation.

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Authorities allege the suspect called in a bomb threat at 1:18 p.m. to L'Anse Creuse Middle School East in Chesterfield Township from her home, saying there were multiple bombs around the school.

They said she used a spoof app to disguise her real phone number and tried to deepen her voice to sound like a man. She's accused of calling the school again at 1:52 p.m. and screamed into the phone that bombs were around the building, according to the release from Smith's office.

It also states that the suspect is alleged to have used the same app to call Roseville Middle School in Roseville at 1:37 p.m. stating: "There are bombs placed all around your school." She called back 11 minutes later and said: "You have 30 minutes," then hung up, according to the release.

Multiple police agencies used K-9 units to search both schools. They found no evidence of bombs at either school property.

Last Thursday, a day after the threats were made, Chesterfield Township Police said they were completing juvenile petitions charging two 13-year-old L'Anse Creuse Middle School East girls, both of whom are in the eighth grade and live in the township.

Police said in its release that the girls tried to hide their identities when making the bomb threats by using a cellphone spoof app. It stated the detective bureau was able to defeat the app and obtain confessions.

Neither police nor the prosecutor's office stated in their releases why the girls were suspended from school.

Smith said his office "will remain vigilant, never underplaying the serious nature of such threats. Our children’s lives depend on it."

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The same day as the threats were made in Macomb County, Melvindale Police announced an arrest on social media after threats of possible violence forced the school district there to cancel classes for three days.

A threat involving Melvindale-Northern Allen Park schools was first reported the night of Sept. 15, prompting school closures starting Sept. 16. Buildings remained closed through Wednesday.

Melvindale Police posted on Facebook on Sept. 17 that the threats made two days earlier were via a social media site, using an anonymous third party app. Later on Sept. 17, police posted a screenshot of an online conversation that indicated "there's going to be two shooters one in the high school and one in the middle school."

Melvindale Police did not provide additional details when announcing the arrest in the school threats case.

Contact Christina Hall: chall@freepress.com. Follow her on Twitter: @challreporter. The Associated Press contributed to this report.