In a conversation recorded by federal investigators, a Chinatown businessman brags about delivering $35,000 to Mayor Vincent C. Gray in one week and asks, according to his lawyer, “Who else can do that?”

The details of the recorded conversation emerged in a court hearing Monday in the case of D.C. restaurateur Anthony C.Y. Cheng Sr. and his son, who have been charged with conspiring to bribe District officials in a taxicab licensing scheme.

Cheng, who goes by “Tony,” and his son have pleaded not guilty, and his attorney Ken Robinson said after the hearing that there was nothing improper about the money described in the recorded conversation.

The elder Cheng, Robinson said, hosted two fundraisers for Gray (D), providing the food and the venue — his namesake restaurant on H Street, NW. The events raised roughly $35,000, mostly from other Asian American business leaders, he said.

“Cheng did not ever touch those checks,” Robinson said.

The charges against the Chengs come as U.S. Attorney Ronald C. Machen Jr. is pursuing allegations of political corruption in the city, including an off-the-books “shadow campaign” to help Gray’s mayoral bid. Gray has not been charged and has denied any wrongdoing.

The money for Gray that Cheng mentions in the recording is not at issue in the government’s case against the father and son, who are accused of paying off public officials to obtain licenses to run two taxicab companies. But attorneys for the Chengs said they want to ensure that the recorded conversation from the undercover operation is not used against the two men if their case proceeds to trial, which is tentatively scheduled to begin in December.

Assistant U.S. Attorney Lionel Andre told U.S. District Judge Ellen S. Huvelle that he had provided the Chengs’ lawyers with the name of a potential witness who could explain the reference to the money. Robinson said in court that the person is, Reuben O. Charles II, who was Gray’s transition director.

Charles could not immediately be reached for comment.

The indictment filed in June does not implicate any elected officials. Cheng and his son are accused of allegedly agreeing to pay the chairman of the D.C. Taxicab Commission 10 percent of their profits in exchange for help getting the licenses. Leon Swain was the chairman at the time. Swain had already served a high-profile role as a law enforcement informant in another case by the time he met with Cheng at one of his restaurants in 2011.

The exact timing of the recorded conversation disclosed on Monday has not been made public. Cheng and his son were allegedly seeking the licenses in November 2010, according to the indictment. One of the meetings with Swain allegedly took place in January 2011.

In 2012, Cheng was among dozens on a host committee for a birthday celebration for Gray and fundraiser for a constituent-services fund.