A bomb threat caused significant traffic disruptions on Interstate 90 near Island Crest Way on Mercer Island Saturday afternoon. The incident began around 12:45 p.m. when Bellevue police stopped a vehicle and the driver allegedly threw an object resembling an explosive device. Two individuals are in custody, and a bomb squad is responding. Traffic was severely backed up, with delays reported from Lake Sammamish to Seattle. Mercer Island police advised the public to avoid the area, assuring that there was no ongoing threat.