Cell phones as bugging tools

This is old but I never new this:

FBI taps cell phone mic as eavesdropping tool | Tech News on ZDNet

The FBI appears to have begun using a novel form of electronic surveillance in criminal investigations: remotely activating a mobile phone's microphone and using it to eavesdrop on nearby conversations

The technique is called a "roving bug," and was approved by top U.S. Department of Justice officials for use against members of a New York organized crime family who were wary of conventional surveillance techniques such as tailing a suspect or wiretapping him.
Nextel and Samsung handsets and the Motorola Razr are especially vulnerable to software downloads that activate their microphones, said James Atkinson, a counter-surveillance consultant who has worked closely with government agencies. "They can be remotely accessed and made to transmit room audio all the time," he said. "You can do that without having physical access to the phone."...

Nextel and Samsung handsets and the Motorola Razr are especially
vulnerable to software downloads that activate their microphones, said James Atkinson,
a counter-surveillance consultant who has worked closely with
government agencies. "They can be remotely accessed and made to
transmit room audio all the time," he said. "You can do that without
having physical access to the phone."