A woman and child were injured early Friday morning in a one-vehicle crash south of Oak Harbor.

Both were taken to Whidbey General Hospital in Coupeville.

The driver, 48, is under investigation for vehicular assault, the Washington State Patrol reported. Troopers believe alcohol was a factor in the crash, according to an accident memo.

The Coupeville woman was driving a 2007 GMC pickup truck southbound on Zylstra Road at Hastie Lake Road when it crossed the centerline and struck a tree, troopers reported.

Her passenger — a 9-year-old child whose gender was not reported — is from Lake Stevens.

The crash remains under investigation.