EVERETT — An investigator from the Snohomish County Medical Examiner’s Office was more than three hours into his shift when he was arrested Sunday and accused of driving drunk to the scene of an alcohol-related crash that ended four lives, officials said.

An internal probe at the medical examiner’s office is looking into whether the investigator had been drinking before or during his regularly scheduled shift, which began at 4 p.m. and was supposed to go until midnight.

“The whole thing’s under investigation,” said Carolyn Sanden, deputy director of the medical examiner’s office.

The investigator, who is 48 and lives in Seattle, has been with the office for eight years.

The Herald incorrectly reported Tuesday that he was on call when he responded to the traffic scene. In fact, he was on duty and supposed to be at the office or responding to calls, Sanden said.

Around 6:15 p.m., a Ford Explorer ran a stop sign on 108th Street NE at Highway 9 northeast of Marysville, struck a Hyundai sedan and killed all four people inside. The Ford’s driver, who was arrested for investigation of four counts of vehicular homicide, told police he had eight beers before getting behind the wheel. The 27-year-old Snohomish man remained jailed Tuesday.

The Washington State Patrol typically conducts on-scene crash investigations before calling the medical examiner, Sanden said.

Troopers called the medical examiner’s office to Sunday’s deadly crash at 7:04 p.m., trooper Keith Leary said. The investigator drove a county vehicle. Once there, a trooper smelled alcohol on his breath and pulled him aside.

The investigator blew into a portable breath-testing device and submitted to another breath test at a nearby police station, Leary said. He was cited for drunken driving and given a ride home.

In keeping with State Patrol policy, Leary declined to release information about the recorded blood-alcohol level pending completion of the investigation.

Officials have said that the crash scene was not compromised.

The medical examiner’s investigator is on leave while the incident is being reviewed, Sanden said. She couldn’t say how long that would take.

Jackson Holtz contributed to this report.

Noah Haglund: 425-339-3465, nhaglund@heraldnet.com.