Imagine standing at a bus stop, talking to your friend and having your conversation recorded without you knowing.  It happens all the time, and the FBI doesn't even need a warrant to do it.

Federal agents are planting microphones to secretly record conversations.

Jeff Harp, a KPIX 5 security analyst and former FBI special agent said, "They put microphones under rocks, they put microphones in trees, they plant microphones in equipment. I mean, there's microphones that are planted in places that people don't think about, because that's the intent!"

FBI agents hid microphones inside light fixtures and at a bus stop outside the Oakland Courthouse without a warrant to record conversations, between March 2010 and January 2011.

Federal authorities are trying to prove real estate investors in San Mateo and Alameda counties are guilty of bid rigging and fraud and used these recordings as evidence.