Former Las Vegas Raiders coach Jon Gruden is suing the NFL over the scandal that led to his resignation last month, accusing the league of waging a "malicious and orchestrated" campaign to destroy his career.

Gruden's lawyer Adam Hosmer-Henner, who filed a civil suit in Las Vegas on Thursday, said in a statement the league and commissioner Roger Goodell had "selectively" leaked to media offensive emails sent by the former Raiders coach.

Gruden, 58, stepped down as Raiders coach on October 11 after the emergence of a trove of old emails in which he used racist, misogynistic and anti-gay language.

The emails were uncovered as part of a broader NFL investigation into the Washington Football Team and allegations of workplace misconduct at the franchise. Gruden was working as a television analyst at the time.

"The complaint alleges that the defendants selectively leaked Gruden's private correspondence to the Wall Street Journal and New York Times in order to harm Gruden's reputation and force him out of his job," Hosmer-Henner said.

"There is no explanation or justification for why Gruden's emails were the only ones made public out of the 650,000 emails collected in the NFL's investigation of the Washington Football Team or for why the emails were held for months before being released in the middle of the Raiders' season."

CBS Sports reported last month that Raiders owner Mark Davis believes the team and Gruden were targeted by the league.

"[Davis] thinks the league office is out to get him," one unidentified source told CBS. "He thinks it's a hit job."

The NFL said in a statement the allegations in Gruden's lawsuit were "entirely meritless." 

It said league officials hoped to force Gruden's departure from the Raiders after leaking an email to the Wall Street Journal in which he used a racist trope to disparage NFL players union chief DeMaurice Smith.

When Gruden remained in his job after that bombshell, the lawsuit alleges the league leaked a second wave of damning emails to the New York Times.

"When their initial salvo did not result in Gruden's firing or resignation, Defendants ratcheted up the pressure by intimating that further documents would become public if Gruden was not fired," the lawsuit stated.