Akkerman was last seen in Spokane, Washington on August 7, 1987. He worked as a cabdriver for the Checker Cab Co.. He picked up a male customer at Fifth and Wall, near Deaconess Medical Center, at 12:20 a.m. Akkerman told his dispatcher he was taking the man to the Spokane Valley. He has never been heard from again. Two hours later, another cab driver found Akkerman's cab at Fifth and Madison, just four blocks from where he'd picked up his last fare. The vehicle was unlocked, the windows were rolled down and the knife Akkerman carried for protection was next to the driver's seat.

Akkerman was a good employee and neither his employer nor his wife believe he left of his own accord. The fare he picked up the night of his disappearance was never identified. His case remains unsolved.