Washington State Patrol investigators have concluded that no “criminal activity” was involved in the disappearance of a Bellevue woman, whose van was found abandoned on a Bainbridge ferry in January.

According to a WSP press release, witnesses interviewed in the investigation placed Stafford-Yilmaz at the ferry terminal and onboard the ferry Puyallup Jan. 13. Investigators did not find evidence that Stafford-Yilmaz got off the ferry on Bainbridge or in in Seattle, the release said.

WSP has been investigating the disappearance of Stafford-Yilmaz since when her Ford Windstar was found unattended on a evening sailing from Seattle to Bainbridge. Some personal items belonging to Stafford-Yilmaz were found outside on an upper deck of the ferry.

WSP, U.S. Coast Guard and local police departments conducted a lengthy search for Stafford-Yilmaz on the night of her disappearance.

Stafford-Yilmaz is still listed as a missing person. WSP will reopen the case if more information becomes available, according to the release.