Officials have released the 911 calls from a Westchester native who desperately tried to get rescuers to help as his friend was attacked by a mountain lion in Washington.

Byram Hills graduate Isaac Sederbaum made the calls only moments after a cougar bit his head and attacked his friend.  His friend, 32-year-old Seattle cyclist SJ Brooks, was later killed by the animal.

The two were mountain biking in the Cascade Mountains a week ago when the incident occurred.

Sederbaum, an Armonk native who now is a Washington state resident, managed to flee the scene, despite gashes to his head.

At one point, he handed over the phone to a passerby, who talked to the dispatchers.

Brian Kerston was among the wildlife crews who rushed to the scene and killed the cougar. Kerston has studied cougars for nearly two decades and says the animal was barely 4 years old and weighed only 80 pounds.  He says it was about 100 pounds less than what he should have weighed.

Kerston has also tagged nearly 200 cougars and says this one was different: it came back after the two mountain bikers initially fought it off.

"The determination and the persistence and the aggressiveness of this cat was exceptionally unusual,” he says.

A GoFundMe page has been set up and already raised $4,000.