The contempt of court case against Sheriff Joe Arpaio took a stunning twist on Thursday when the sheriff admitted to the federal judge that he had secretly investigated the judge's wife.

The surprising revelation came after Arpaio finished answering questions about how he had repeatedly violated U.S. District Judge Murray Snow's orders, which is the topic of the contempt hearing.

Snow then asked Arpaio, while he was still on the witness stand and under oath, "Are you aware that I have ever been investigated?"

Ultimately Arpaio admitted he had received a tip from an email about something Snow's wife was allegedly overheard saying at a restaurant.

When asked about what the email said, Arpaio told Snow, "I think it mentioned that Judge Snow wanted to do everything to make sure I am not elected."

Arpaio said his legal team hired a private investigator to confirm the tip.

KJZZ's Jude Joffe-Block was in court and spoke with Steve Goldstein.

Updated 4/23/2015 at 10:07 p.m.