New court filings allege federal authorities tapped Comptroller John Liu's phone as part of its criminal investigation into his campaign operation. NY1's Courtney Gross filed the following report.

John Liu didn't know they were listening.

His phone was tapped as part of a more than two-year federal investigation into his campaign operation.

"It's surprising," he said. "In hindsight, if they wanted to listen in, I got a three-way feature on my phone."

The eavesdropping, which allegedly included 10 wire taps over 18 months on at least five different people related to the Liu campaign, was revealed in court papers on Monday.

"I am sure the authorities are doing what they feel is necessary," Liu said. "I don't second guess how people do their job. As I said, the more information people have, the better it is for everybody."

Liu's former campaign treasurer, Jenny Hou, and a former fundraiser, Oliver Pan, are charged with attempting to get over-the-limit campaign donations to Liu, donations that could have been eligible for public matching funds.

In a motion to dismiss the charges, Pan's attorneys claim the government had ulterior motives.

"The government just rushed ahead and cut corners because apparently they were obsessed, and I don't use this lightly, with making a case, manufacturing a case against John Liu," said Pan attorney Irwin Rochman. "Pan is really collateral damage."

In his own filing, Gerald Lefcourt, the attorney for Liu's former treasurer, said that
"The government's investigation has used many tactics in the obsessive pursuit of John Liu."

The documents, including email exchanges and the notes of an undercover FBI agent, provide never-before-seen details of the federal investigation.

It all culminates at a Pan fundraiser in August 2011, where Pan's lawyers allege the undercover FBI agent suggested Pan collect illegal campaign donations for the comptroller.

"He tells them from the outset [that] he can't say the Liu campaign knew these were straw donors," Rochman said

Both Hou and Pan are scheduled to be back in court on Friday. As for the comptroller, he said the investigation has not changed his plans for 2013.