18 November 2015 Last updated at 15:00 GMT
Det Ch Supt David Sandall said it was proving an "extremely traumatic time for her parents" and they are now treating the disappearance of the 15-year-old, from Measham, as murder.
The teenager has not been seen since about 18:00 GMT on Friday when she was dropped off outside Ibstock Community College.
Two men, aged 27 and 28, who were arrested on Monday on suspicion of kidnap have been re-arrested on suspicion of murder.
More updates on this and other stories from Leicestershire.
The police officer leading the search for missing Leicestershire teenager Kayleigh Haywood has told her family to prepare themselves for the worst.