"Our investigative team will continue to work at the scene in the area around Orrell Water Park for the next few days".
Ellen's friends told police they last knew her to have gone to Orrell Water Park.
A student who dreamed of becoming a doctor died of multiple neck wounds after a "brutal attack" at a beauty spot, police have revealed, as they said the killing could have had a sexual motive.
Detective Superintendent Howard Millington has stressed the investigation "is still in its early stages".
GMP said it is leaving no stone unturned in the investigation and asked for the public to get in touch if they had seen anyone acting suspiciously in the area on Friday or in the days before.
A huge search had been launched after the couple reported their daughter missing at 7.20pm on Friday.
Ellen's parents Mike, a successful businessman, and Kay, 48, a school head teacher, were being comforted by family liaison officers at their home in Worsley, Greater Manchester today.
"Don't worry that you'll be wasting my time, any bit of information, no matter how small could be vital".
"There will be a large police presence in the area for some time as we investigate and also on the streets surrounding the area as a precaution".
Det Supt Millington said he was "keeping an open mind" about whether the murder was sexually motivated. "R.I.P. Ellen".
Police previously said Ellen's disappearance was "extremely out of character".
Sixth-former Ellen Higginbottom, 18, was discovered dead on the edge of a field in Wigan early on Saturday 13 hours after she disappeared.
"The post-mortem has now taken place and we have a clearer picture of what may have happened to Ellen, but we are still piecing together her exact movements in the lead-up to her death".
Anyone with information should contact police on 0161 856 7103, call 101 or ring the independent charity Crimestoppers on 0800 555 111.