I am glad the police caught the person that broke into your garage.
The trolley is in 2 parts. The inner trolley is attached to the cable on one end and the chain on the other. These 2 parts should travel together unless the emergency release is pulled.
If you pull the emergency release, the outer trolley is released from the inner trolley and the door can travel independent of the chain and cable. When the outer trolley goes over the inner trolley, the latch should catch and join the outer trolley to the inner trolley.
I think the bike thief broke the trolley on your garage door opener. You need to replace the trolley assembly. The assembly comes with the outer and inner trolleys and the emergency release mechanism assembled together.
I am sending some images of how to attach the cable and chain to the trolley and the inner and outer trolleys.