This was an older single family home in a rough part of northern Phoenix with high vagrant traffic. The home had sat empty for a couple months while we did some sewer line replacements. It was cleaned up and updated nicely, and passed the pre-move in inspection with no hint of trouble. A few days after move in, we got a complaint from the tenants because they weren't getting any A/C blowing out of the register in the main bedroom even though the rest of the house was working fine. The tech went out and found a makeshift living space complete with mattress, a urine jug and other personal belongings set up in the attic above. The person had detached the vent so it would blow directly on them! We don't know how long they've lived up there and we never caught anyone anyway. The best we could figure is they were gaining access by climbing a nearby tree and going through a gable vent.

Needless to say, we repaired the A/C, trimmed the tree and secured the attic! We also worked out a deal to transfer the tenants to another property. We did eventually re-lease the house and never had a problem since.