Last November, as Democrats were stuck in seemingly endless negotiations over President Joe Biden’s Build Back Better legislation, White House reporter Josh Boak received a tip: Sen. Kyrsten Sinema, an Arizona Democrat who staunchly opposed tax increases targeting private equity, had reaped a substantial campaign cash windfall from the industry.

Boak and his Washington colleague, national political reporter Brian Slodysko, set out to document just how much the industry had given to Sinema, while fact-checking her claim that private equity provided a vital lifeline to the economy of Arizona. The two juggled their daily beats while using their spare time to report out the story.

Their reporting was shelved, however, when West Virginia Sen. Joe Manchin said in December he wouldn’t vote for the bill, effectively pulling the plug on the legislation. That changed abruptly when Senate Democrats announced late last month they had struck a deal with Manchin, including a narrowing of the so-called “carried interest” loophole that Sinema and private equity had fought so hard to preserve.

Slodysko dusted off the pair’s previous reporting and conducted a line-by-line review of Sinema’s campaign contributions since then, which yielded a stunning finding: Sinema’s acceptance of campaign contributions from the industry had skyrocketed to nearly $1M over the past year — more than double what she had received in her previous 10 years in Congress combined.

With Democrats needing every vote in the evenly divided Senate to pass any legislation, Sinema forced her party to remove the carried interest provisions from the bill. Then, as Slodysko was wrapping up his reporting, Sinema struck again: During a marathon series of weekend votes, she worked with Republicans to effectively exempt private equity from another tax provision in the bill, which other massive businesses will still have to pay.

A line-by-line review of Sinema’s campaign funding revealed contributions from the private equity industry skyrocketing.

Slodysko circled back to some of his sources who provided an email from financial industry lobbyists cajoling moderate Democratic senators to oppose the tax provision, which Sinema ultimately helped remove from the bill. He also leveraged details from his reporting to get others involved in the fighting the legislation to provide additional information about their last minute lobbying push to kill the tax measures.

A day after the legislation passed the Senate with the tax provisions excised, the AP story drove political coverage and earned hundreds of thousands of views on AP News. The story was cited in The Daily podcast from The New York Times, among others.