Democrat Tom O'Halleran kept Arizona's Congressional District 1 seat blue with a decisive victory over Pinal County Sheriff Paul Babeu Tuesday.

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O'Halleran, a former Republican, defeated Babeu, the subject of an ABC15 investigation involving his role overseeing an abusive Massachusetts boarding school.

Babeu had scant support from national Republicans in the Democratic-leaning district spanning Flagstaff to the Tucson suburbs.

O'Halleran had his own issues to overcome. He was a Republican in the state Legislature from 2001 to 2009, ran for House as an independent in 2014 and registered as a Democrat last year.

He takes over for Ann Kirkpatrick, who left the seat to run -- unsuccessfully -- against John McCain in the U.S. Senate.

McCain also won handily on Tuesday.

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