The FBI arrested Honolulu police officer Derek Hahn on Wednesday in connection with an ongoing federal corruption investigation targeting Hawaii law enforcement.

Hahn, a lieutenant who once worked in the Honolulu Police Department’s Criminal Intelligence Unit, is believed to be a co-conspirator in the alleged framing of Gerard Puana.

He is the third officer arrested by the FBI this week in connection with the case.

Cory Lum/Civil Beat

Officer Minh-Hung “Bobby” Nguyen and retired HPD major Gordon Shiraishi were arrested Sunday for allegedly taking part in the frame job and lying to federal investigators.

Both Nguyen and Shiraishi worked with Hahn in the Criminal Intelligence Unit, which is a secretive division of HPD that conducts surveillance and gathers intelligence in organized crime and terrorism cases.

Michelle Yu, a spokeswoman for HPD, said that Hahn was most recently assigned to the Communications Division. She said he has been placed on unpaid leave pending an investigation.

Nguyen has also been placed on unpaid leave. Shiraishi retired from HPD in April.

Hahn was released from custody Wednesday on $50,000 bail after making an initial appearance before U.S. Magistrate Judge Richard Puglisi. A preliminary hearing in his case is scheduled for Oct. 31.

Hahn is charged with felony conspiracy. He was described in court by Assistant U.S. Attorney Janaki Gandhi as the HPD officer who “called the shots” when it came to setting up Puana.

Hahn’s attorney, Birney Bervar, said the conspiracy allegations are overblown, and that his client did not participate in any attempt to frame Puana.

Puana was accused of stealing former police chief Louis Kealoha’s mailbox in June 2013.

But Puana’s defense attorney, Alexander Silvert, said he uncovered evidence that his client was framed by Kealoha and his wife, Katherine, a deputy city prosecutor, in an attempt to settle a family dispute over money.

Puana is Katherine Kealoha’s uncle, and he had filed a lawsuit against her accusing her of bilking him and his mother out of hundreds of thousands of dollars.

In a written statement, FBI Special Agent in Charge Paul Delacourt said that Hahn’s arrest is just one more step in an ongoing investigation into public corruption in Hawaii.

The FBI has been investigating the case for nearly three years.

“The FBI is conducting a thorough investigation into allegations of public corruption and will exert every legal effort to ensure those responsible are investigated and prosecuted,” Delacourt said.

“In order to restore the public’s trust in its law enforcement, we are required to root out all responsible parties. This investigation is not over and we will continue to follow the facts wherever they lead us.”

Read the criminal complaint here: