Another one bites the dust.

The Liberals fired a third candidate this week after New Democrats revealed the man used an F-word gay slur on Facebook, raising questions about the vetting process for would-be Liberal MPPs in the June 2 election campaign.

The termination of Chatham-Kent-Leamington hopeful Alec Mazurek was announced 30 minutes after Liberal Leader Steven Del Duca was caught off-guard by the revelation at a Scarborough news conference on mental health supports.

“Mr. Mazurek has officially been terminated,” Liberal press secretary Andrea Ernesaks said in a statement.

Del Duca had pledged to drop Mazurek if the revelations were true, and said “irresponsible” and “reckless” comments from his party’s candidates would not be tolerated.

“That is not what we stand for,” Del Duca told reporters.

“We believe in making sure that our candidates are … reflective of what our values are, not just as a party but as a province, around tolerance.”

He did not explain how the party’s vetting process missed the social media post in question.

New Democrats released screen grabs of the offending comment, and another using the word “bitches.”

The firing came a day after Liberals axed their Parry Sound-Muskoka candidate, Barry Stanley, who published a baseless theory on the cause of homosexuality. As first revealed by the Star, Stanley wrote about it in a 2009 self-published book and told the Star he did not flag it for the Liberals in the vetting process, which included an interview.

Mazurek was a long-shot in Chatham-Kent-Leamington, a riding that has mostly been held by Progressive Conservatives in recent years.

On Tuesday, Liberals dumped 18-year-old Aidan Kallioinen as their candidate in Sault Ste. Marie. The reason for his dismissal was not disclosed.

It is often difficult for political parties to field candidates in ridings where they are not traditionally strong and have low odds of winning, as was the case for Stanley in the Progressive Conservative stronghold of Parry Sound-Muskoka.

In Kitchener, Progressive Conservative Leader Doug Ford held his first news conference in days, where he defended PC candidates including Stephen Lecce, his education minister. Lecce has apologized for participating in a fraternity “slave auction” while he was a student at Western University in 2006.

“He’s acknowledged that it was inappropriate and he’s apologized for attending this event as a teenager. Mr. Lecce has been a strong advocate of combating racism in schools and he has my full support,” said Ford.

“This is something he did when he was 19 years old and in university. But let me tell you something about Stephen Lecce … he’s passionate about fighting for marginalized communities.”

Appearing with Del Duca in her riding of Scarborough-Guildwood, Liberal incumbent Mitzie Hunter said Lecce’s participation in the auction does not make racialized students feel safe in the school system.

“Trivializing, mocking, joking about the trans-Atlantic slave trade is not OK,” added Hunter, who is Black. “It was a horrific experience for Black Canadians and Black people in North America, and it still is today.”

Ford was far less empathetic when asked about revelations that some Tory MPPs — including Lisa MacLeod, his tourism minister — supplemented their six-figure salaries with riding association funds.

“I’ll be pretty frank, I wasn’t too happy when I when I found out about this,” he fumed in the wake of reports that MacLeod, who earns $165,851, receiving $44,000 from her Nepean PC riding association between 2018 and 2020. At least seven other Tory MPPs also got payments from their riding associations.

“I’ve been assured that all rules were followed, the expenses are independently audited, they’re reviewed and approved by Elections (Ontario),” he said.

But Ford said after the June 2 election, he wants “to sit down with all the parties” and ensure the practice ends.

“I want to take a good hard look at these rules and tighten them up.”

Del Duca said earlier this week that he would examine the rules as well.

Rob Ferguson is a Toronto-based reporter covering Ontario politics for the Star. Follow him on Twitter: @robferguson1