Other federal agents spent much of the day searching the Antioch home of Anthony Warner.
Realtor Steve Fridrich contacted the FBI after reading Warner's name, as for several years, a man by the name of Tony Warner had worked for him for several years doing information technology work.
Fridrich confirms that agents asked him whether or not Warner had paranoia about 5G technology.
Fridrich told the agents that Warner had never spoken to him about that.
But a source close to the federal investigation said that among several different tips and angles, agents are investigating whether or not Warner had paranoia that 5G technology was being used to spy on Americans.
A spokeswoman for the FBI said they could not comment because of the pending investigation.
Fridrich described the Tony Warner who worked for him as a kind person who they contacted only to work on internet issues.