More post mortem tests have been taking place and specialists experts have been brought in as part of the hunt for Libby Squire's killer.
The 21-year-old Hull university student went missing four months ago after a night out.
Her body was found in the Humber Estuary, around 20 miles from Grimsby Docks, six weeks after her disappearance.
Police are treating her death as homicide.
Detective Superintendent Martin Smalley, who is leading the investigation, said: “My sincerest thanks go out to Libby’s parents for their patience and understanding while we endeavour to return Libby to them as soon as we can.
"The results of the post-mortem examination were not released at the time. As further tests have since been undertaken with results pending, details are as yet, unable to be released."
Humberside Police has revealed search specialists as well as experts in forensics and oceanography are helping the investigation.
Libby was reported missing in the early hours of Friday, 1 February, after a night out with friends.
An extensive police search and investigation was launched the same day.
Det Supt Smalley added: “Libby’s death is being investigated as a homicide with numerous enquiries, analysis and examinations continuing to take place.
“There is a dedicated team of detectives working on the investigation. There is an unprecedented amount of work taking place behind the scenes, and the investigation is ongoing with Libby still very much at the forefront of our minds.”