Police performed a Pursuit Intervention Technique, or PIT, maneuver on westbound I-84 between 33rd and 12th avenues, according to Portland police.
Two people, including Bossy, were taken into custody a few minutes later.
Around 3 p.m., Vancouver police also arrested Nenemeny W. Ekiek, 21, who was booked into the Cowlitz County Jail on suspicion of first-degree murder.
Investigators say Bossy and Ekiek were with D’Anthony Leslie Williams, 19, when he allegedly fatally shot 30-year-old Kayla Chapman, a clerk at the Kelso Quik Chek Market, on Jan. 22. Chapman was the only person in the store at the time. Williams was arrested in Camas the next day.
A white four-door sedan driven by Bossy arrived at the store before Chapman was shot. Ekiek was a passenger in the vehicle, according to a Kelso police press release.
Both directions of I-84 are closed from I-205 to the Cesar Chavez Boulevard exit as police continue to investigate, according to the Oregon Department of Transportation. The highway was expected to be closed for hours.