family feud that almost turned fatal in cleveland, where an theseologist has been charged with attempted murder after attacking his son-in-law. And alex perez is tracking the case. Reporter: This... See More
family feud that almost turned fatal in cleveland, where an theseologist has been charged with attempted murder after attacking his son-in-law. And alex perez is tracking the case. Reporter: This morning, a quiet cleveland suburb is in disbelief, that had panicked neighbors, calling 911. 911 emergency. Someone is yelling for help loudly. Reporter: That's after seth allen harper left his home for the airport, to visit his daughter, living in florida with his estranged wife. As harper walked towards the car, police say a man jumped out of the bushes, wearing a black ski mask and blue surgical gloves. There's someone screaming for help. We're on our way. Reporter: Bleeding after repeated blows to his head, harper fought back. Breaking his arm and pinning him down. When he heard the man scream, allen, get off me, I can't breathe. Police say that's when harper realized he knew who was behind the mask. A well-known anesthesiologist and his own father-in-law. He sacrificed his profession, his career and quite possibly his freedom, just to go after his son-in-law. Reporter: Police say the 66-year-old doctor also had a backpack filled with syringes and different anesthetics, a screwdriver and more surgical gloves. I think there's little doubt it's premedicated. Reporter: Part of the motive? Harper and his daughter are in the middle of a contentious divorce. He drove through the night from his neighborhood in allentown, pennsylvania, to carry out the attack. Police arrested him, charging him with attempted murder, felony assault and kidnapping. He's not responding to calls for comment. But out on bail, due in court SEPTEMBER 25th. For "good morning america," alex perez, abc news, chicago. Let's bring in dan abrams. Brad garrett said, it's premedita premeditated. This guy drives six hours. Took someone else's car. Gets there. Begins the process of attacking the son-in-law. The son-in-law who is younger and bigger overtakes him. And he says, allen, I can't breathe anymore. The attacker is now begging him to stop because he's losing the fight. This is one of the more bone-headed attempted murder schemes I've ever seen. And now facing real time. Yeah. This is attempted aggravated murder, basing probably up to 25 years behind bars for this. This is serious stuff. In addition to the drugs he had with him. You have to think, he's dexter morgan? He's going to inject him with these drugs and he's going to pass out? This whole thing is right out of a b-rate movie. What kind of charges could he face for having the drugs on the scene? There's additional drugs there. Those aren't going to be anything compared to the aggravated murder charge. Those will probably be swept in along with the other charges. The attempted aggravated murder that's the big one here. They're not just saying he went there to hurt him. Or to harm him. They're saying -- the authorities say they believe he went there to kill him. Wow. Yeah. Dan abram, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.