Arizona Senator John McCain is backing Paul Babeu, who is facing charges that he threatened to have his ex-lover, a Mexican national, deported.

The 43-year-old Babeu, the sheriff of Pinal County, Arizona and a GOP candidate for Congress, denied the charges during a press conference on Saturday, but acknowledged he's gay.

Babeu, a vocal opponent of illegal immigration, was featured in a 2010 McCain campaign ad advocating for greater border security.

“Well, of course, Sheriff Babeu is a friend of mine,” McCain is quoted as saying by ABC News. “I do not know the details except what has been published in the media and I am sure there will be a thorough and complete investigation if there is any allegations of wrongdoing. All I can say is that he also deserves the benefit, as every citizen does, of innocence until proven guilty.”

Babeu's accuser, identified only as Jose in a Phoenix New Times story, claimed that Babeu had threatened him with deportation when he refused to sign an agreement stating that he would not discuss their relationship.

Babeu told reporters that he had stepped down as a co-chairman off Mitt Romney's Arizona campaign. However, he vowed to continue his campaign to represent the people of Arizona's 4th Congressional District.

(Related: Paul Babeu notes Ron Paul's gay marriage stance at coming out presser.)