Carlos Vega moved this week toward suing Philadelphia District Attorney Larry Krasner’s campaign, a political action committee supporting Krasner, and an activist who cofounded that group, adding a late twist to their combative Democratic primary contest.

Vega, Krasner’s opponent in the May 18 election, on Tuesday filed a notice of his intent to sue. He said in a statement Thursday that activist Shaun King, Real Justice PAC, and Krasner’s campaign have “targeted maliciously false and misleading rhetoric … to defame him in an effort to dissuade Philadelphians from voting for the change this city needs.”

Vega also said he has “called on Larry Krasner to stop King’s incendiary lies, but he has not,” which has “caused relentless online harassment and bullying” for him, his supporters, and family.

Krasner’s campaign said Vega’s legal filing shows he thinks “no one should criticize him or ask hard questions” about his 35 years as a prosecutor in the city.

“Carlos Vega is angry because people are asking questions that expose his deeply troubling record as a prosecutor,” the campaign said in a statement. “He doesn’t want to answer those questions, as we all saw in last night’s debate.”

» READ MORE: 4 takeaways from the only TV debate between Philly DA Larry Krasner and challenger Carlos Vega

The brewing legal fight comes as the primary heats up, and it kicked off a day before the race’s only televised debate Wednesday, a rancorous back-and-forth that continued with the candidates trading barbs after the cameras turned off.

Louis Tumolo, Vega’s attorney, said he may file a full complaint as soon as next week.

“It’s clear they’re coordinating messaging,” Tumolo said of Krasner, King, and Real Justice PAC.

Trevor Maloney, Vega’s campaign manager, said the legal action was prompted by a Facebook post by King last week that linked to an 18-minute podcast, in which he calls Vega “a real-life supervillain” for his record as a prosecutor.

Real Justice PAC, based in San Francisco, supports Krasner and has paid for some of his campaign staffing. The group filed a complaint last week with the Philadelphia Board of Ethics, saying a political action committee that opposes Krasner, Protect Our Police PAC, had missed a deadline to disclose how it is raising and spending money. Protect Our Police filed the report after the complaint.

» READ MORE: Carlos Vega is making Philly DA Larry Krasner fight for his job as the election nears

King, a prominent criminal justice reform advocate, has appeared at events with Krasner. He responded to Vega’s legal filing Thursday on his website, calling it “hot garbage.”

King included in his response details of the case of Anthony Wright, who won a $10 million settlement from the city after he was exonerated in a 2016 retrial of his 1991 conviction for rape and murder.

Vega, who was one of the prosecutors in the retrial, has repeatedly said he was a late addition to the trial team and not responsible for the decision to go forward. DNA evidence available before the retrial showed a different man committed the crimes.

Krasner brought up Wright’s case several times during Wednesday’s debate, prompting Vega to complain that “he keeps talking about it.”

“This tactic, of abusing court processes in civil court by filing baseless lawsuits, parallels Vega’s abuse of court processes in criminal court by prosecuting Tony Wright after any reasonable person knew with certainty that Wright was innocent,” Krasner’s campaign said. “It is unacceptable for any prosecutor, much less a chief prosecutor, to behave this way.”

Krasner fired Vega and 30 other prosecutors during his first week in office in 2018. Vega sued Krasner and the city in 2019, saying he was fired due to age discrimination. That suit is pending in federal court.