DETROIT -

The search is on in Detroit's Marina District for a carjacker that went on a violent crime spree Thursday morning, crashing a car into a canal and shooting a security guard.

It all started at a BP gas station at Montclair and E. Jefferson Avenue.

Sharlonda Buckman had just dropped her child off at school and stopped at the gas station to get aspirin.

"He said, 'Get out of the car.' At first, I was a little shocked and then noticed he had a gun and I screamed," Buckman said.

As the carjacker took off with Buckman's SUV, Jason McQuire, the manager of Riverside Marina, decided to get involved.

He and another man started chasing the carjacker.

“The lady was getting carjacked and me and another gentleman tried to help her out. The man started shooting. The guy took off with her car and turned up the street. I knew it was dead end at the Edison Boat Club," McQuire said.

The chase continued until the carjacker crashed through the locked gate at the boat club, jumping out of the SUV.

The SUV then crashed into a canal.

Gunfire was exchanged between the carjacker and the security guard.

The guard was hit in the arm and police said the guard thinks he also hit the carjacker -- but the carjacker then stole the guard's blue 2009 Ford Focus with tinted windows and fled.

The carjacker is armed and should be considered dangerous.

"It was mind-blowing for me. I'm upset, but I'm also encouraged that at the time when I needed somebody, people who didn't know me came to my rescue," Buckman said.

The Focus' license plate is CDU-0204.

The carjacker is described as black, 5 feet 9 inches tall, 150 pounds, slim with a goatee. He was wearing a blue hooded sweatshirt and gray vest.