2008 Volvo C70 rattle in rear of car.

What is your question?

Sounds like it's coming from the back tires. Just put new tires on. Oil change and visual inspection by mechanic revealed no leaks, cracks, and no loose bolts, etc. Took apart trunk, but found nothing moving or loose. It clunks and sounds like a heavy box of rocks banging. The sound comes from the rear of the car and seems to come more from the passenger side. Thanks for you help!

What makes this problem better or worse?

slower speeds and bumps or potholes

How long has your 2008 Volvo C70 had this problem?

about a year