Booker left the Trenk DiPasquale law firm in 2006 when he was elected mayor, but received five checks from the firm from 2007 to 2011, according to the Post. The firm received, during that time, more than $2 million in fees from local agencies over which Booker had some influence.

Booker told the Post that the payments from the firm were “a settlement buyout for [his] interest in the firm," but neither he nor his campaign would disclose how much he received from the firm overall.

“I had an equity stake, and we had a negotiated settlement,” Booker said.

The firm told the Post that “since Mr. Booker left the firm in 2006, he has provided no services or work to the firm.”

Booker is a heavy favorite to win Tuesday's New Jersey Senate Democratic primary, and Democrats are favored to regain the seat in the general election.

But Booker's career prior to and alongside his time serving as Newark mayor has come under scrutiny in recent weeks, with likely GOP opponent Steve Lonegan seizing on a New York Times report on Booker's Silicon Valley connections and how they've helped his tech startup. Lonegan has not yet commented on the Post report.

--This post was updated at 3:30 p.m. to clarify the agencies from which the firm collected fees.