FIFE, Wash. — A tow truck driver was killed after he was struck by a semi-truck on Interstate 5 in Milton Tuesday morning, according to the Washington State Patrol (WSP).

The crash happened on northbound I-5 just south of Porter Way around 6:15 a.m. WSP Trooper Robert Reyer said the 65-year-old driver of the FedEx semi-truck was arrested for suspicion of DUI.

WSP identified the tow truck driver who was killed as 49-year-old Joe Masterson. According to the towing company, he was a father of four and had worked with the company for six years.

Two right lanes of northbound I-5 were closed for over four hours while police investigated. All northbound lanes reopened to traffic around 10:50 a.m., according to the Washington State Department of Transportation (WSDOT).

The WSDOT said drivers should “expect it to take a while for the backup to clear.”

According to WSP, the victim was strapping down a box truck onto his tow truck on the shoulder of I-5 when he was struck and killed. The WSP said the semi-truck veered onto the shoulder, missed the tow truck and only struck the victim.

Reyer said vehicular homicide charges are expected to be filed against the 65-year-old man who was driving the semi-truck.