Snohomish resident Matthew McDonald pleaded guilty Wednesday to four counts of vehicular homicide, two of which were Tom and Hilda Woods, the son and daughter-in-law of former Kirkland Mayor Bill Woods.

McDonald, 27, faces up to 8 1/2 years in prison for killing the four adults. But as a result of a plea agreement prosecutors will ask for 6 1/2 years. Sentencing will take place March 16.

According to prosecutors, McDonald had a blood alcohol level of .123 when he and a passenger climbed into his Ford Explorer after drinking beer for nearly 12 hours. The legal limit for blood alcohol content in Washington State is .08.

McDonald then ran a stop sign at 108th Street N.E. in Snohomish at a high rate of speed, smashing into the small Hyundai that the Woods and friends Brad and Melissa Agerup were in. The two couples were returning home after planning a birthday party.

McDonald initially walked away from the crash scene and arrived at a nearby house. According to court documents, McDonald told a woman who lived at the house he was worried about a drunk driving charge: “My God what have I done?” The woman took McDonald back to the scene.

One investigator with the Snohomish County Medical Examiner’s Office, who arrived at the crash scene drunk, was fired in December after an investigation into the incident.