PHOENIX (AP) — Arizona Gov. Jan Brewer is walking away from Attorney General Tom Horne and instead endorsing his opponent in the August Republican primary.

Brewer's endorsement of Mark Brnovich was announced Thursday by the former state gaming director's campaign.

The endorsement from the state's top Republican is a major blow for Horne. It comes as he faces two investigations into allegations that he is illegally using his staff to run his re-election campaign.

The attorney for the former Horne staffer who alleges Horne was using his state-paid staff for campaign work now says she has been interviewed by Maricopa County investigators in an apparent third investigation.

Brewer's endorsement statement didn't mention Horne by name. Instead she said she wants an attorney general "who will fill the office with integrity and compassion."