The Washington Football Team owner is calling out Mary Ellen Blair, whom he describes as a former executive assistant in the team's offices. In docs filed Monday morning, Snyder claims Blair -- who was first demoted and then fired in 2017 -- contacted a current team employee in late May or early June to say a Washington Post story was coming out that would "not [be] good for Dan." Snyder insinuates she used stolen information, such as team contacts, to fish for negative information for that story.

BTW, The WaPo story that came out on July 5 claimed "minority owners" of the Washington Football Team are pissed at Snyder and wanted to sell their stakes.

According to the docs, obtained by TMZ Sports, Blair contacted team employees again in early July, and said another big story was coming out claiming Snyder did "dirty and illegal" things.

He claims Blair told one employee, you'd "probably make a lot of money" for info on Snyder. Sources connected to Snyder tell us he also has recordings of Blair and multiple affidavits indicating she actually offered bribes to contacts.

Snyder, who's hired high-powered attorney Joe Tacopina, says the employee didn't take the bait, and points out the WaPo story that was published July 16 alleged sexual harassment in Team offices ... but he was not accused.

However, around that time meaww.com did post stories alleging Snyder was involved in sex trafficking and tied to Jeffrey Epstein. As TMZ Sports first reported, he's filed a $10 million defamation lawsuit against the site, and now wants a judge to allow him to dig into Blair's recent contacts, her finances ... and especially her housing.

Snyder claims she's lived in a swanky apartment for years -- despite being in "dire financial straits" -- and says within the last 60 days she upgraded to an even higher-end home.