VATICAN CITY—The Vatican on Saturday arrested a diplomat recalled from Washington last year amid investigations in Canada, the United States and the Vatican for possession of child pornography.

A Vatican statement said that Monsignor Carlo Capella was being held in gendarmerie barracks inside the Vatican, and that his arrest follows a Vatican investigation.

Police in Windsor, Ont., said Capella allegedly uploaded child porn to a social networking site while visiting a place of worship from over the 2016 Christmas holiday. In the statement, Windsor police accused Capella of accessing, possessing and distributing child pornography.

Windsor police issued a Canada-wide arrest warrant for Capella last September. They say they were alerted by the RCMP in February 2017 and launched an investigation, eventually getting judicial permission to access relevant internet records.

The Vatican recalled Capella, the No. 4 in its Washington embassy, after the U.S. State Department notified it on Aug. 21 of a “possible violation of laws relating to child pornography images” by one of its diplomats in Washington.

At the time of the Sept. 15 announcement about Capella’s recall, neither the Vatican nor the State Department made any mention of a Canadian angle to the case.

Capella was a high-ranking priest in the Vatican’s diplomatic corps. He served on the Italy desk in the Vatican’s secretariat of state and was part of the official delegation that negotiated a tax treaty with Italy before being posted to the U.S. Embassy last year.

A canon lawyer, Capella is listed online as having written a 2003 paper for the Pontifical Lateran University on priestly celibacy and the church’s criminal code.

The Diocese of London, Ont., confirmed that it helped investigators who had suspicions of “possible violations of child pornography laws by using a computer address at a local church.”

It declined further comment, citing a police request.

With files from The Canadian Press