(CNN) -- The electronic component visible in a law enforcement image of an intercepted suspicious shipment from Yemen appears to be a printed circuit board from a disassembled cell phone, an engineer told CNN Friday. "This size and the shape of the PCB (printed circuit board) are typical to a handset cell phone type device," wrote Olivier Clerc, hardware application engineering manager for a large U.S.-based cell phone parts manufacturer. Clerc prepared the e-mailed analysis of the image at CNN's request. His analysis was supported by information from a source close to the investigation into two U.S.-bound suspicious packages, who said the devices appear to be designed to be detonated by a cell phone.
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NEW: Source: Devices in packages appear to be designed to be detonated by a cell phone
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The electronic device was found in a suspicious package bound for the U.S. from Yemen
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The size and shape of the device are typical to a cell phone, expert says
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Cell phones have been widely used by terrorist groups to trigger bombs
A @placeholder official says while the explosive was likely the highly volatile PETN, testing is ongoing.