Tirupati Urban police have sounded a red alert in the temple city, following the alleged involvement of some Students Islamic Movement of India (SIMI) activists in the Choppadandi bank robbery and the surprisingly-higher ramifications the issue has taken, with a similar incident reported from Burdwan (West Bengal). With fingers pointing to a Tirupati-based educational society, which is believed to be a beneficiary of the tainted funds, the police have got down to checking vehicles entering the city and zeroing in on likely hideouts. A close vigil has been kept on the activities of the society and the members are being monitored from close quarters, a top police official said.