The police are yet to nab the assailants. The discom, too, is not certain about what triggered the violence.

According to BSES officials, the assailants arrived in two vehicles.

“They seemed to have come well prepared,” an official said. “When the guards on duty tried to stop and question them, they thrashed them.”

Armed with hockey sticks and iron rods, the assailants beat up three BSES meter readers when they tried to intervene, says the FIR lodged at Sarojini Nagar Police Station.

Two of the injured officials were taken to Safdarjung Hospital, and were discharged later.

Though the assailants fled before the PCR could arrive, Sarojini Nagar police later arrested three of the accused. They were charged with causing grievous injury.

BSES maintains that they were unaware of the reason for such an altercation, police sources, on the other hand, said the incident was the result of a “personal tiff” that the injured BSES officials had with the accused.