The federal prosecutor investigating the case of a Pennsylvania school district that spied on its students via remote-controlled laptop cameras says the school district won't face criminal charges in the case.

US Attorney Zane David Memenger said in a statement that there is no evidence the Lower Merion School District, in suburban Philadelphia, had any criminal intent when it remotely activated cameras on laptops issued to students.

"For the government to prosecute a criminal case, it must prove beyond a reasonable doubt that the person charged acted with criminal intent," Memeger said, as quoted at Information Week. "We have not found evidence that would establish beyond a reasonable doubt that anyone involved had criminal intent."

The issue came to light in February, when the parents of Harriton High School student Blake Robbins filed a class-action lawsuit alleging the school district invaded Robbins' privacy by filming him in his home through his school-issued laptop. It emerged later that the school district photographed Robbins 400 times in a two-week period, in various states of undress and even during his sleep.

Investigators found that the remote-controlled cameras took some 56,000 pictures of Lower Merion School District students over a two-year period, with the cameras sometimes left on for weeks at a time.

The school district claimed initially it used the remote-operated cameras to locate lost or stolen laptops. But the Robbins lawsuit alleges that the school district used the cameras for other purposes. In Robbins' case, the 15-year-old student was confronted by a vice principal over what the school official thought was drug use. The vice principal saw a pill in Robbins' bedroom, which the plaintiffs say was simply candy.

The FBI launched an investigation of the school district in February, but the US Attorney's findings have effectively put an end to any criminal law issue in the matter.

The prosecutor's conclusion "supports the findings of our internal investigation and follows ... approval of new laptop policies by the school board," Lower Merion School District Superintendent Christopher W. McGinley said, as quoted at PCMag. "This is all good news for the students and staff of Lower Merion School District as we prepare for the start of a new school year."

The school district has adopted a new policy that sets guidelines for when the laptop cameras can be used by school officials, and requires parents to sign off on use of the cameras, or decline participating in the school's program to issue laptops to students, the Philadelphia Inquirer reports.

The lack of criminal charges doesn't mean the school district is off the hook. The Robbins' civil lawsuit is still before the courts, as is another lawsuit, this one launched last month by student Jilal Hasan.

The Philadelphia Inquirer reports that the school district has already spent $1 million defending itself against the lawsuits.