Banana Sam was 19 years old when he died on Thursday from complications related to heart disease, according to the zoo.
On Dec. 30, 2011, zookeepers discovered the monkey was missing from his enclosure and that someone had breached a perimeter gate, climbed onto the roof of the squirrel monkey exhibit and cut holes in the mesh wiring.
An investigation was launched and a $5,000 reward was offered. The next day, a man came forward with the monkey, saying he found it in San Francisco's Stern Grove and lured it into his backpack, police said.
No arrest has been made in the case, police said Friday.