The lost tablet computers are among iPads used last year in a 13-school trial run by the Los Angeles Unified School System, which plans to equip each student in the nation's second-largest school system with the devices in a $1 billion program, the Los Angeles Times reported.
The problem is most acute at one school, the Valley Academy of Arts and Sciences in Granada hills. Administrators said they distributed 1,200 iPads there last year, and 69 were not returned.
The search for the missing computers comes after a security breach, involving about 300 iPads, was discovered last week.
The school board's Technology Committee extensively questioned Chief Information Officer Ron Chandler, at a meeting Wednesday about the discovery some students bypassed security measures on new iPads to access restricted social websites, the newspaper said.
Chandler said officials are working to draft a "progressive discipline matrix" to deal with varying types of computer misuse.
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