The family of a Prince George’s County high school student has filed a lawsuit alleging campus security illegally searched the teenage boy after a classmate reported her cellphone missing.

Devonte Woods, 15, a student at Central High School in Capitol Heights, alleges that campus security searched him and about 20 other students in a classroom to look for the phone on the morning of Oct. 1.

Campus security “explained that a student in her class got her phone stolen and the class had 30 seconds to come up with the stolen phone,” according to the lawsuit filed Wednesday. “No one in the class had the phone. So, after 30 seconds, the three male security officers began to search every student’s binder and school bag.”

Tracking down a student’s missing phone — which turned out to have been left at home, according to the suit — is not a good reason to invade students’ privacy, said Jimmy Bell, an attorney representing Woods’s family.

Bell said the search not only violated school-system policies but it was also illegal because there was no “reasonable suspicion” the teen had the phone.

“Security guards are only supposed to search students when there is a danger,” Bell said. “This is a cellphone, and they treated my client like a criminal.”

Prince George’s schools officials declined to comment on the allegations, citing the pending litigation.

Bell said security staff searched Woods’s binder and person — similar to searches on other students in the class — and found nothing.

Woods’s parents visited campus administrators after the incident to confront them about the search, Bell said. Officials told Woods’s parents that the school changed policies to ban searches­ of students for cellphones, which aren’t allowed on campus, and to require administrators be present during searches­ deemed appropriate, the lawsuit stated.

But Bell said school officials should have adhered to those rules from the start.

“That’s like kicking in the door of someone’s house and then saying, ‘Oh, we made a mistake,’ ” he said.