A Catholic priest in Alabama has officially married a recent high school graduate, four months after the pair fled to Italy, according to a marriage certificate filed in court.

Alexander Crow, 30, married the 18-year-old former student of McGill-Toolen Catholic High School on Friday. He met her whilst volunteering at the school. 

Their legalised union was presented in a document received by the Mobile County Probate court on Monday.

Most Rev Thomas Rodi, Archbishop of Mobile, has said he intends to seek Crow’s permanent removal from the clergy, an extremely rare disciplinary measure.

The archdiocese described Crow's actions as “totally unbecoming of a priest” and abandoning his assignment.

Mobile's County Sheriff’s Office and the District Attorney’s Office investigated Crow over allegations that he engaged in sexual misconduct with the teen or groomed multiple girls at the high school.

But a statement from the local district attorney confirmed no charges would be filed against him.

According to WKRG TV station, the teen “declined to answer any questions” of investigators about her trip to Italy with Crow after a subpoena was issued.

“She appeared in seemingly good health and said that she is safe,” the statement said.

“Without being able to speak with the young lady about these events, we do not have sufficient admissible evidence to charge a crime at this point. Therefore, this investigation is currently closed”.

Investigators found a letter Crow sent to the girl on Valentine’s Day, when she was still 17, declaring they were already married.

But the marriage license filed jointly in their names in Mobile listed the wedding date as last Friday.

The document, which prominently lists Alabama’s minimum age of marriage as 16, affirms: “Each of us is entering into the marriage voluntarily and of our own free will and not under duress or undue influence.”