(KFOR) -- A German Shepherd dog was critically injured after being thrown over a bridge, high above I-40 Wednesday afternoon in eastern Oklahoma County.

The animal is now being cared for by a local veterinarian as Oklahoma County Sheriff's Deputies search for the person responsible.

Authorities learned from the original owner that the dog's name was "Rookie."

He's lucky to be alive.

"Yes, because he could have gotten hit by a car or anything could have happened after and who knows how long he laid out there," Kate Bellah said, Deer Creek Animal Hospital veterinary technician."

"This is just a tragic, really sick situation," Sheriff's Spokesman Mark Myers said. "For someone to take a defenseless dog and just toss it off of a bridge over a major interstate, I really don't understand how someone could do something like that."

Myers said a truck driver traveling along I-40 saw the incident while nearing the S.E. 59th St. bridge.

An OHP trooper found him bleeding profusely with an open fracture on his leg, as well as skid marks.

Read more at KFOR's website.