A series of harassing text messages from a student to classmates escalated to a bomb threat at Phoenixville Area Middle School on Tuesday, police said.

Police say they intend to charge the eighth-grade student who allegedly sent the messages. They said they planned to discuss the case with the Chester County District Attorney's Office on Wednesday.

The school was evacuated late Tuesday afternoon, after classes had ended. Police used bomb-sniffing dogs to check the school and did not find anything.

Investigators believe the incident was a prank and no one was in danger, said Bill Mossman, Phoenixville police chief.

"However, until we can be sure that a threat is a hoax, we must act out of caution and initiate our protocols," Mossman wrote in an email. "Prank or not, this was a serious situation which caused great concern to students and their parents and took a lot of law enforcement resources to solve."

The eighth-grade student sent the first harassing text messages Sunday night. On Monday, the messages turned more threatening. By Tuesday afternoon, they included threats to bomb the school, Mossman said.

The parents of the students who received the threatening messages told school officials about them around 4 p.m., shortly after their children had received the messages.

The student masked his number, but sent all the messages to middle school students, so police and school administration concentrated their investigation on the middle school and found the student after serving a series of search warrants, Mossman said.

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