REDMOND, Ore. -- Oregon State Police detectives have found a motor home owned by a missing McMinnville couple.

Kenneth Miller, 73, and Betty Lou Japel, 69, were pronounced missing last week. Their motor home was discovered by police Wednesday in the latest twist of a bizarre case.

The investigation into the couple's disappearance began after the shooting of an Arizona police officer May 17. Gregory Cole, also known as Groundhog, was a suspect in the shooting and was also connected to Miller and Japel, according to state police.

On Wednesday, Cole was found dead after police said he shot and killed himself.

Also on Wednesday, police seized the missing couple's 1976 Sportscoach motor home after learning it was being secured at the National Guard Tank Battalion facility in Redmond. Military officials who knew the couple said they were keeping the motor home secure after Bureau of Land Management personnel found it in July 2006.

Detectives searched the motor home and found evidence that tied the couple to Cole.

Miller and Japel have been together for 30 years, but never married, according to a McMinnville police report. They do not have a permanent address, and have traveled extensively in the U.S., police said.

Japel and Miller's family said they have not heard from the couple in about a year. However, police said it was common for the couple to go a year or more without contacting their family.

Anyone with information related to the case is asked to call 503-434-6500.