The feds are probing several of City Comptroller John Liu’s financial backers who weren’t listed as bundlers during his 2009 campaign — as well as a confidant who currently works for him.

As part of the criminal complaint filed against Liu campaign treasurer Jia “Jenny” Hou, authorities subpoenaed the records of Mei Hua Ru, the comptroller’s powerful office scheduler who was his treasurer during the 2009 campaign.

Hou, 25 — who was charged with aiding illegal fund-raising through “straw” donors — was a campaign volunteer who worked under the veteran political operative Ru three years ago.

When Ru stepped down from the campaign to take a post in the Comptroller’s Office in 2010, Hou was named to serve as campaign treasurer.

As part of its case against Hou, Manhattan US Attorney Preet Bharara submitted an Oct. 19, 2009, e-mail that Ru sent to Hou, advising her of a fund-raiser organized by one of Liu’s backers.

Like several others, fund-raiser Cheng Rui Lu, was not listed by the Liu campaign as a bundler — someone who was collecting donations for the candidate — which could violate city campaign-finance rules.

Hou, in an e-mail response, lists three donors who also appear to have been raising funds for the campaign, but who were not reported as bundlers.

“Chel Dong Chang — $17,500. Hugh Mo — $19,800. Cheng Rui Lu — $12,300,” Hou responds to Ru, listing the names of Liu fund-raisers.

The feds have sought records for all three fund-raisers, according to a subpoena issued to Hou.

Lu, a businessman, accompanied Liu to China in 2007. An employee at his office said Lu was in China and could not be reached.

Chel Dong Chang was a Korean fund-raising chair for Liu’s campaign, a source said.

Hugh Mo is a lawyer and a former deputy NYPD commissioner. He declined comment.

Ru declined comment on the fund-raisers.

Liu ducked questions on the growing fund-raising probe following a Lunar New Year celebration in Chinatown yesterday.

“I feel very privileged to be in a position to serve New Yorkers and will continue to do so,” Liu said several times before departing.

Additional reporting by Sabrina Ford and Chuck Bennett