CASTLE ROCK, Wash. (AP) — A woman faces manslaughter charges following a crash on Interstate 5 that killed three people near Castle Rock. The Washington State Patrol says it is investigating whether 43-year-old Anna-Christie Ireland was driving under the influence when her vehicle struck a vehicle parked on the side of the highway Saturday. The impact pushed the second vehicle into a tow truck driver at the scene. KOIN-TV reports the tow truck driver and two passengers in the parked vehicle were killed. The identities of those killed weren’t immediately released. The patrol says Ireland is under investigation of three vehicular manslaughter charges. It wasn’t immediately known if Ireland had a lawyer who could speak on her behalf.