A federal grand jury is investigating Honolulu Police Chief Louis Kealoha and his wife, city Deputy Prosecutor Katherine Kealoha, Federal Public Defender Alexander Silvert said Friday.

The investigation was triggered by the federal “mailbox case,” involving the alleged theft of the Kealohas’ mailbox from their Kahala home in June 2013, Silvert said, but the grand jury is focusing on a June 2011 incident.

Silvert represented Katherine Kealoha’s uncle Gerard Puana, who was accused of stealing the mailbox, and turned over information to federal officials after a mistrial was declared in Puana’s case.

Silvert contended Puana was framed to discredit him in a state civil case in which he and his mother sued Katherine Kea-loha.

“We developed information concerning corruption related to the mailbox case and turned it over to the FBI, and they’ve been running with it since,” Silvert said.

Silvert said he found evidence of corruption, and based on his request, Michael Wheat, a special prosecutor, was appointed by the U.S. attorney general to investigate this case.

The U.S. Attorney’s Office dismissed the mailbox theft case against Puana after a mistrial was declared in December 2014 when Louis Kealoha made an unsolicited statement regarding Puana having been charged and convicted of breaking into a neighbor’s home.

Silvert said the chief’s remarks about Puana breaking into a neighbor’s home referred to a June 27, 2011, incident when a neighbor called police after Puana stepped into the neighbor’s screened-in porch and yelled about parking in his stall. Police arrested him on suspicion of unauthorized entry into a dwelling.

While Puana was at the police station, Silvert said, two civilian witnesses saw Katherine Kealoha, accompanied by police officers, enter Puana’s locked home. Puana lived there with his mother, Florence Puana, who is Katherine Kealoha’s grandmother.

Gerard Puana alleged items, including documents and cash, were missing from his home when he returned, Silvert said.

“Many of the people who were there (before the grand jury) yesterday were directly related to that incident,” including police officers and Wheat, Silvert said Friday.

In the civil case, Katherine Kealoha’s 95-year-old grandmother, Florence Puana, sued Kealoha for $1 million over a reverse mortgage on the grandmother’s house. Gerard Puana also sued Kealoha for $70,000 for money he claimed to have given her to invest and for safekeeping.

Kealoha countersued, testifying the money she spent on her own expenses was reimbursement for money her grandmother asked her to use to buy a condominium for Gerard Puana.

A jury awarded Katherine Kealoha $658,787 in damages, assessing all the damages against the uncle for making misrepresentations and abusing the legal process.

The Puanas alleged Katherine Kealoha used $23,976 from the reverse mortgage to pay for her husband’s inauguration breakfast and thousands in lease payments for her car. They are appealing the verdict.