Bicycle detail

Brian and Donna (inhabitants of 10852 SE Stark St, RV Lot 3, Portland, Oregon, 97216) approach me offering to purchase this bike. Brian took it for a "test ride" then about 5 minutes later Donna told me Brian intended to steal it to begin with and she was not going to help him pay for it. Next Donna said she had to run errands and told me I had to leave her property (they both invited me to their home to discuss the sale). When I questioned this Donna told me Brian was the "bike king". I told her in person and Brian over the phone they must return the bicycle or I would report it to law enforcement. Donna became combative and argumentative saying it was Brian's fault and she did not know where he was going or when she would see him again (they are married and reside together and remain so after the fact). Over several more phone calls and text messages throughout the day Brian became angry and made death threats towards myself and other witnesses saying they would be shot and he had a gun. The matter was reported to Portland (Oregon) Police Bureau's East Precinct Special Property Crimes and Robbery Detective's Unit.