By Phil Fairbanks | News Staff Reporter |

He was the mayor’s gatekeeper, chief political strategist and top policy adviser.

And now, he’s talking to the FBI.

Former Deputy Mayor Steven M. Casey, the man often credited with orchestrating Byron W. Brown’s climb to power, has met at least twice with FBI agents investigating public corruption, according to three sources with knowledge of the investigation.

No one is certain what Casey is telling the FBI, but the three sources said he is believed to be cooperating with the federal and state probes into political operative G. Steven Pigeon, his former mentor and an on-again, off-again political ally. Pigeon was recently indicted on nine felony counts, most involving bribery.

From Day One, Casey, who has not been charged with any crimes, has said he’s not a target of the investigation, but two of the sources familiar with the probe said they believe he is one now.