NEW YORK (CBSNewYork) — Police on Monday were looking for a gang of alleged subway vandals who caused an electrical explosion on a Brooklyn subway line last week, and may be behind many other subway pranks.

As CBS2 Political Reporter Marcia Kramer reported, a video posted to YouTube showed an explosion of sparks after a southbound C Train hit something on the tracks at the Nostrand Avenue stop in Bedford-Stuyvesant, Brooklyn.

Sources said vandals put a piece of metal on the tracks, and when the train went over the metal piece, it hit the third rail and exploded. Police said they have witnesses to the vandalism, and have recovered the metal.

The explosion, which Metropolitan Transportation Authority officials called an electrical arc of sparks, triggered the emergency brakes on the train and halted service around 8 p.m. last Thursday – during the busy morning rush – for more than an hour.

The operator got out of the train personally and removed the metal piece during the delay, sources said.

“Anything could have happened — that’s terrible,” said Amber Turner of Bedford-Stuyvesant.

Sources told CBS2 the explosion could be a gang of high school vandals who might also be behind a spate of incidents on the transit system. The video comes after similar recent reports of teenagers putting metal on the tracks in order to create such displays, CBS2’s Jessica Schneider reported.

Police also have been investigating a possible connection between the explosion video and another one, where vandals are seen repeatedly reopening the doors of a subway car and preventing the train from leaving the station.

Sources told CBS2 the probe is following an online trail that includes an assortment of photo posts – showing a person changing a train’s destination signs, explaining how he stole a train sign, and trespassing underground.

The video of the subway explosion was posted to YouTube by rail fan Max Diamond, in order to alert the Metropolitan Transportation Authority and the NYPD.

“This happened several times before, and it’s absolutely ridiculous,” Diamond said. “It’s unsafe for passengers, for the operators, conductors and whatnot. So by putting this on YouTube, maybe the MTA will do something.”

The MTA responded immediately.

In a statement, the MTA’s Adam Lisberg said if the video is real, “it is unconscionable that vandals would have deliberately endangered the lives of our customers and employees, as well as delayed thousands of customers during the morning rush.”

The MTA said it will work with police to identify and arrest those involved.

Police are investigating the incident as a case of criminal mischief, sources told CBS2.

Sources said one of those believed to be involved has been arrested before for a subway-related violation.