Mussolini was an atheist.
Mussolini was married in the Catholic Church, had his children baptized in the Catholic Church. He made contraception and divorce illegal in Italy, and made Catholicism the State Church of Italy. He was close with numerous Cardinals and Bishops right up until the time of his death.
Truly odd behavior for an atheist, wouldn’t you say? He may have been atheist at some point in his life but it’s clear he didn’t remain one.