India, Oct. 5 -- The New York police ramped up their probe into the unfortunate death of two teenage girls who were killed on Saturday while subway surfing on top of a J train crossing the Williamsburg Bridge.

The two girls, one confirmed to be 13 and the other believed to be between 13 and 15, were killed from head injuries after reportedly striking a low-hanging beam while riding the final car of the Queens-bound train.

The incident occurred around 3:10 am as the train approached the Marcy Avenue station in Brooklyn.

According to the police, the emergency brake was triggered as the train entered the station, prompting the conductor to investigate-- only to discover the two lifeless bodies on the roof of the train.

As of Sunday, poli...