(CNN) - A news helicopter crew in Chicago captured video of an amazing rescue early Tuesday morning.
The dog was drinking from Lake Michigan and leaned too far over, tumbling into the water.
The dog struggled to get back onto the concrete, but couldn't get a grip.
A police officer who was responding to a nearby car crash rushed over to help the dog.
After the dramatic rescue, another officer was able to get a leash on the dog.
Police believe the dog ran out of one of the vehicles and toward the lake.
The officers then got the dog into a police SUV and drove away. They are looking for the owner.