If there was one phrase that irked critics of Lower Merion School District's 69-page report on how, when, and why it secretly activated webcams on student laptops, it might have been the two words in large type on the cover:

Independent Investigation.

How, some wondered, could the review truly be independent if the investigators were lawyers and computer experts hired by the school district?

On Wednesday, a federal judge took a step that could quell those concerns, ordering the district to share some of its computer evidence with a consultant for the family suing Lower Merion over the webcam monitoring.

The order, signed by U.S. District Judge Jan E. DuBois, was drafted by lawyers for the school district and Blake Robbins, the Harriton High School sophomore whose invasion-of-privacy suit in February brought the monitoring to light.

Mark S. Haltzman, the attorney for Robbins and his parents, said he had always intended to verify any findings presented by the district.

"You never rely on the defendant to conduct the evaluation and investigation," he said.

Henry E. Hockeimer Jr., the former federal prosecutor who led the school district's 10-week investigation, declined to comment.

For the probe, Hockeimer's firm, Ballard Spahr L.L.P., had enlisted the computer-forensics firm L-3 to scour district servers and the computers of Lower Merion staffers who used the now-disabled LANrev tracking software or received images from it.

In their May 3 report, the investigators said the system had snapped more than 58,000 photos and screen shots since it was first implemented in September 2008. Most were from laptops that students had reported missing, but thousands of the images came from webcams that no one turned off even after the computers were returned to students.

In essence, the order signed Wednesday allows the Robbinses' computer expert to run his own tests to see if the steps taken by the district's investigators were sufficient to locate all of the photos captured by the webcams.

The order requires L-3 Communications Holdings Inc. to let that expert, John Steinbach, copy a mirror image of the hard drive of the computer used by a network technician, Michael Perbix.

Perbix was one of only two Lower Merion employees who had the know-how and the authority to remotely activate webcams on student laptops, and the one who did it most often. Each image was automatically marked with a "signature" from LANrev.

He also was the staffer who was asked to turn on the webcam on Blake Robbins' laptop last October, the district's report said.

Using the signatures, Steinbach's goal is to compare the number of images he finds on Perbix's drive with the number that L-3 reported finding.

According to the judge's order, "Mr. Steinbach's testing will not require him to actually view any images but rather only the computer-generated code related to such images."

Steinbach will also be allowed to take a sample image captured by LANrev and see if he can alter it to hide or eliminate the signature. If he can, that would raise the possibility that district employees could have taken such steps, and that district investigators might not have found all the relevant images.

The investigators' report concluded that there was no evidence that school employees spied on students or that the webcams snapped any inappropriate images. But it faulted Lower Merion administrators and technology staffers for a lack of disclosure and mismanagement of the theft-tracking system, and for failing to set up strict policies to protect students' privacy.

The judge signed an injunction last month barring the district from using such invasive technology without written consent from students and parents. And district officials have vowed to make extensive changes.

One of Perbix's bosses, information-systems coordinator Carol Cafiero, spent more than six hours Tuesday answering questions under oath from the Robbinses' attorney as part of the lawsuit. In an earlier deposition, Cafiero had declined to answer Haltzman's questions, citing her Fifth Amendment right against self-incrimination.

Her attorney, Charles Mandracchia, had said that Cafiero had nothing to hide, but that he wanted her to first talk to the FBI, which had launched its own investigation.

Tuesday's deposition was smoother, Mandracchia said. "Every question that was proposed to her, she answered," he said.

Contact staff writer John P. Martin at 610-313-8120 or jmartin@phillynews.com.