BART dispatchers illustrate 5 minutes of chaos in Saturday robbery

The first warning sign of the 50-odd teenagers that hopped BART fare gates at Coliseum Station in Oakland Saturday before beating and robbing passengers of a car they commandeered came with a warning from a dispatcher.

“Be advised of three juveniles, nasty ones, over the fare gates at Coliseum,” the dispatcher said at 9:19 p.m., according to a recording of BART’s police radio channel provided by Broadcastify.

The whole episode, in which dozens more teens followed the first trio over the gates and beat and robbed at least seven people, was over in less than five minutes, according to the transit agency.

The radio recording illustrates the frenetic pacing of the crime and the difficulty police had in tracking down the suspects before they disappeared into the surrounding East Oakland neighborhood.

BART police said they arrived at the station in less than five minutes, but the youths were already gone.

The unusual episode raised questions of whether BART had adequate police staffing at the Oakland station, and the transit agency said it would amp up officer staffing in the area.

In all, six people said they were robbed on the Dublin-bound train and a seventh on the platform, and a police report said at least two victims sustained injuries to the head that required medical attention.

Minutes after the first fare-hoppers were reported at 9:19 p.m., dispatchers said they were scanning surveillance cameras at the station to try to track down the suspects, some of whom were “still loitering on the platform.”

A conductor of the train in question came on the radio, saying he estimated 30 “kids” boarded his train.

A train leaves the Coliseum BART station on Tuesday, April 25, 2017, in Oakland, Calif. A train leaves the Coliseum BART station on Tuesday, April 25, 2017, in Oakland, Calif. Photo: Special To The Chronicle / Noah Berger Photo: Special To The Chronicle / Noah Berger Image 1 of / 17 Caption Close BART dispatchers illustrate 5 minutes of chaos in Saturday robbery 1 / 17 Back to Gallery

He said he saw them “beat up someone, rob them and then run off the train.”

Seconds later, the dispatcher said the group got on the train, “started beating the windows” then ran off the train when the doors were re-opened before beating up another man on the platform.

Added a second dispatcher, “a group of 50 just bum-rushed the entire train.”

BART Wednesday said its investigators had identified some of the suspects and were working with local police agencies to obtain warrants for their arrest.

Michael Bodley is a San Francisco Chronicle staff writer. Email: mbodley@sfchronicle.com. Twitter: @michael_bodley