By Jessica Oh
Louisville, KY (WLKY/CNN) - We're learning more about a young man accused of carjacking a Louisville woman.
He allegedly led police on a high-speed chase, and its dramatic end was caught on tape.
"I just can't believe it was Aaron," said Paul Wallace.
Hearing why his grandson was arrested Monday is upsetting for him.
[Reporter]: "Does that surprise you?"
"It does. It doesn't sound like Aaron. It don't sound like him at all. He's never has done anything that bad before. Never had," he said.
Until this happened.
Police say it started when Aaron Wallace carjacked a woman in Louisville, then led dozens of authorities on a dramatic chase that ended with a takedown handled by LMPD Officer Timothy Snook and his K-9 named Banjo.
"As the suspect exited his vehicle, I was there to meet him so as he was coming out," said Officer Snook.
Officer Snook says he can understand how the video of Banjo dragging Aaron Wallace out of the car may come across as someone violent.
"Having one dog on an individual, yea it may look dramatic. It looks exciting it may look kind of horrifying to some people but it keeps the suspects safer. It limits liability on the police department's part," said Officer Snook.
Plus, he says it's an effective way to handle potentially dangerous chase suspects.
Officers had no idea what the teen would do as they approached the car Monday.
In fact, Aaron Wallace's grandfather still can't grasp how his grandson ended up in the situation.
[Reporter]: "So it doesn't make sense to you?"
"No it don't make sense at all. The only thing I can figure is he got a hold of some drugs or something. Something happened but I don't know what it was," said Paul Wallace.
What he does know is the young man he raised has a future behind bars, and considering how close Wallace was to graduating high school, the arrest is especially heartbreaking.
"He had just finished everything except taking the final test," said Paul Wallace.
Police said they won't know if Aaron Wallace was under the influence of drugs until toxicology reports come back.
He faces charges including wanton endangerment, robbery and fleeing in Louisville.
He is being held on $10,000 bond in Louisville Metro Corrections.