SAN DIEGO -- A woman was seriously injured by an alleged drunken driver in Pacific Beach, police said Sunday.

The 20-something victim was crossing at the intersection of Mission Boulevard and Reed Avenue about 7:20 p.m. Saturday, when a car driven by Alan Mabrey, 45, hit her while turning left, said San Diego police Sgt. Bob Dare.

The woman suffered head injuries that Dare said were life-threatening.

Mabrey initially walked away from the scene, but returned and was arrested, according to Dare.

Police expect that Mabrey will be charged with felony driving under the influence.

The incident is under investigation.

The woman's name was withheld by police.