A Bothell 23-year-old female driver, identified by Washington State Patrol as Kara Hinrichs, shot and killed herself early Tuesday after a trooper pulled her over on Interstate 90 in Issaquah, patrol spokesman Cliff Pratt said.

At about 2:30 a.m., Hinrichs’ sisters called 911 while they were following her car after she had an alleged domestic dispute with her boyfriend, Pratt added. The trooper caught up with them, moved in behind Hinrichs’ car and directed her to the shoulder of the road on suspicion of driving under the influence. After exiting the patrol car, the trooper heard a gunshot and approached the 2001 green Saturn.

Hinrichs was identified by her driver’s license and her family members, who said that she was a military ranked veteran of the Iraq war, Pratt said.

An investigation is under way by Washington State Patrol detectives.