India, Sept. 2 -- The Delhi Police have collected biological samples from a bus, in which a 16-year-old girl was allegedly gang-raped by its driver and conductor on August 4, recorded statements of a slew of witnesses and compiled footage from CCTV cameras to form a "watertight case", officers aware of the developments said on Tuesday.

They said that the charge sheet in the case is likely to be filed within two weeks. Police said the samples include hair strands of the victim, among other exhibits, which will form a key part of the probe. A police officer associated with the probe, requesting anonymity, said that they have written to the Forensic Science Laboratory (FSL) to expedite the report.

"An official request has been sent to the ...