This was reported by multiple media sources back last year.
Malaysia Airlines MH370 co-pilot's phone 'was on and made contact with network tower' 30 minutes after plane turned around - Asia - World - The Independent
The mobile phone belonging to the co-pilot of the missing Malaysia Airlines flight MH370 was switched on and made contact with a network tower 30 minutes after the plane is believed to have turned back, it has been reported.
A US official, citing information from Malaysian investigators, has told CNN that a network communications tower in Penang, Malaysia, detected first officer Fariq Abdul Hamid’s mobile as it searched for signal.
The official repeated the claims of Malaysia’s acting transport minister, Hishammuddin Hussein, that despite reports at the weekend there was no evidence the phone actually tried to make a call.
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Malaysia Airlines Flight 370: Co-pilot's cell on, U.S. official says - CNN.com
The official told CNN's Pamela Brown on Monday that a cell-phone tower in Penang, Malaysia -- about 250 miles from where the flight's transponder last sent a signal -- detected the first officer's phone searching for service roughly 30 minutes after authorities believe the plane made a sharp turn westward.