PHILADELPHIA -- A suburban school district secretly captured at least 56,000 webcam photographs and screen shots from laptops issued to high school students, its lawyer acknowledged Monday.

"It's clear there were students who were likely captured in their homes," said lawyer Henry Hockeimer, who represents the Lower Merion School District.

None of the images, captured by a tracking program to find missing computers, appeared to be salacious or inappropriate, he said. The district said it remotely activated the tracking software to find 80 missing laptops in the past two years.

The Philadelphia Inquirer first reported Monday on the large number of images recovered from school servers by forensic computer experts, who were hired after student Blake Robbins filed suit over the tracking practice.

Robbins still doesn't know why the district deployed the software tracking program on his computer, as he had not reported it lost or stolen, his lawyer said.

The FBI has opened a criminal investigation into possible wiretap violations by the district, and U.S. Sen. Arlen Specter, of Pennsylvania, has introduced a bill to include webcam surveillance under the federal wiretap statute.

The district photographed Robbins 400 times during a 15-day period last fall, sometimes as he slept in bed or was half-dressed, according to his lawyer, Mark Haltzman. Other times, the district captured screen shots of instant messages or video chats the Harriton High School sophomore had with friends, he said.

"Not only was Blake Robbins being spied upon, but every one of the people he was IM chatting with were spied upon," said Haltzman, whose lawsuit alleges wiretap and privacy violations. "They captured pictures of people that have nothing to do with Harriton. It could be his cousin from Connecticut."

About 38,000 of the images were taken over several months from six computers the school said were stolen from a locker room.

The tracking program took images every 15 minutes, usually capturing the webcam photo of the user and a screen shot at the same time. The program was sometimes turned on for weeks or months at a time, Hockeimer said.

"There were no written policies or procedures governing the circumstances surrounding activating the program and the circumstances regarding turning off the activations," Hockeimer said.

Robbins was one of about 20 students who had not paid the $55 insurance fee required to take the laptops home but was the only one tracked, Haltzman said.

The depositions taken to date have provided contradictory testimony about the reasons for tracking Robbins' laptop. One of the two people authorized to activate the program, technology coordinator Carol Cafiero, invoked her Fifth Amendment right not to answer questions at the deposition, Haltzman said.

About 10 school officials had the right to request an activation, Hockeimer disclosed Monday.

The tracking program helped police identify a suspect not affiliated with the school in the locker room theft, Hockeimer said. The affluent Montgomery County district distributes the Macintosh notebook computers to all 2,300 students at its two high schools, Hockeimer said.

As part of the lawsuit, a federal judge this week is set to begin a confidential process of showing parents the images that were captured of their children.

The school district expects to release a written report on an internal investigation in the next few weeks, Hockeimer said. School board President David Ebby has pledged the report will contain "all the facts -- good and bad."