The Delhi Police suspended two senior officers and issued show-cause notices to two others on Monday for alleged lapses in duty in relation to the brutal gang-rape of the 23-year-old physiotherapist.

Sources also said Delhi police commissioner Neeraj Kumar has told Lieutenant-Governor Tejendra Khanna that police investigations will be complete within seven days and chargesheet will be filed soon after.

Sources said the hearing by a fast-track court is likely to start from January 3 on a day-to-day basis.

Yaadram, Assistant Commissioner of Police (ACP), posted at the Police Control Room's (PCR) southwest district unit, and MS Dabas, ACP Traffic (southern) range, were suspended for dereliction of duty.

"For Dabas, the orders were issued as the bus on which the rape took place had tinted glasses and thick curtains and it was allowed to ply in his area of jurisdiction," said an officer. "Yaadram was suspended for not acting promptly to the distress call of the couple found dumped near the Mahipalpur Flyover. "

Meanwhile, police also issued showcause notices to two deputy commissioners of police including Satbir Singh Katara, additional DCP (PCR) as well as Premnath, deputy commissioner of police traffic (southern range).

Sources at the Tihar Jail, where three of the six are currently lodged, said they were spending their two-week judicial custody amidst tight security and were 'visibly afraid'.