Waukesha Parade Suspect Caught on Doorbell Video Before Arrest

The man police believe plowed into a crowd of people in Wisconsin actually ran to an unsuspecting neighbor for help, moments before he got busted -- and it's all on video.

Darrell Brooks Jr. was captured on a doorbell cam at a home less than a mile from where he allegedly mowed down parade-goers with his Ford Escape. In the video, you see Brooks pounding on the door and pleading for help, saying he'd ordered an Uber that hadn't shown up -- while asking to use the homeowner's phone.

Crazy enough, the neighbor, Daniel Rider, actually obliged ... playing Good Samaritan and inviting the guy inside, making him a sandwich, giving him a blanket and letting him make a call on his personal cell.

Before long, though, Rider says he saw cop cars outside.

Unaware of what had just happened down the street, Rider told NBC News he started to feel nervous and asked Brooks to leave, which he did ... sorta. Brooks lingered on the front porch, and when he saw the police nearby -- he tried getting back inside Rider's home.

It didn't work out for him ... the cops swooped in, and told Brooks to put his hands up, at which point he was arrested.

Brooks has since been booked on multiple charges ... including 5 counts of intentional homicide, with more pending. Word is, he was actually fleeing a separate domestic disturbance when he allegedly drove through parade barricades and ran people over.