Three days after news broke that his campaign fundraising is part of a widening federal investigation, Mayor Bill de Blasio says he's done talking about the topic. NY1's Courtney Gross filed the following report.

Mayor Bill de Blasio says he's done taking questions about a federal investigation of quid pro quos at One Police Plaza that has ensnared his campaign.

"I am happy to take questions today, but I am not going to be speaking about this after today. I have answered a number of questions already. I will answer more, then let's leave it there," the mayor said.

"I hold myself and my administration to the highest standard of integrity," he added.

For the second day in a row, the mayor was dogged by questions about how he knew two businessmen who are now at the center of the scandal. They allegedly provided gifts to top brass at the NYPD in exchange for favors. They were also supporters of the mayor's campaign in 2013. One of them donated thousands to his cause. They also served on his inauguration committee.

"I am obviously sad to hear all of this has happened. It doesn't sound like it's appropriate," de Blasio said. "There is an investigation going underway. We will wait to see what comes of the investigation before making our final judgements. But they are two individuals I just don't know that well."

One of them, a real estate developer named Jona Rechnitz, gave thousands of dollars. His family gave nearly $10,000 for his run for City Hall. Rechnitz bundled another $41,000 for that campaign in 2013. He gave another $50,000 to the mayor's nonprofit group, the Campaign for One New York. That nonprofit was abruptly shut down last month.

De Blasio said the two men received nothing in return for their support.

"I know of no favorable municipal action they got," de Blasio said.

He went on to give an all-out defense of his campaign and his administration. He was also asked whether he had contacted any lawyers.

"Nope, because I have no outreach from any federal or an other agency, and I am confident that we have done things correctly and appropriately and legally. So the answer is no," he said.

Now we know the mayor won't be taking any more questions on this topic any time soon. When asked why, he said all of these questions have been asked and answered.