A 16-year-old boy is in custody after someone fired a gun inside a Metro Transit Bus in Dartmouth Thursday.

Police say Bus #72 was travelling westbound along Pinecrest Drive when shots were fired before 1 p.m.

Police say three young passengers were involved in a verbal dispute which turned into a physical fight.

Police say the bus pulled over in the 100 block of Pinecrest Drive and that one of the teens fired a gun inside the vehicle.

The teens then fled the area on foot in opposite directions.

No injuries were reported.

Mike Falconer, who delivers mail in the area, says he saw the bus pull over to the curb.

“It looked like, from the inside, it looked like there was a fight,” he says. “I was standing right there watching it. I saw two people come out of the bus after the shot.”

He says a young man and a young woman burst out of the vehicle and ran behind an apartment building.

“I heard the shot. I saw maybe the guy with the gun, but I couldn’t recognize him, it was just so quick.”

Police brought in a tracking dog to locate the teens and a 16-year-old boy was arrested around 4:30 p.m.

They are still looking for a white male with a thin build and a tattoo on his collarbone as well as a black female with short dark hair, worn in a ponytail.

Police are reviewing surveillance video from the bus in an effort to identify the teens.

Investigators also interviewed four passengers as well as the driver, who was shaken by the incident.

“We never had anything like this before, so the driver was removed from duty today and will be offered any kind of service we have for employees,” says city spokeswoman Shaune MacKinlay.

Schools in the surrounding area were notified of the shooting and went on lockdown as a precaution.

Police say the schools were advised to proceed with their normal dismissal routine at the end of the day.

With files from CTV Atlantic's Rick Grant