In a statement they said they hoped the 13-year-old's "soul, at long last, can finally rest in peace" now that the serial killer has given his account.
They released the horrific details of her final hours so the public would know the "true heinousness" of Bellfield's crime.
Bellfield would only speak to female officers from Surrey Police when he decided to confess and gave them disturbing details of how he repeatedly raped, tortured and murdered Milly.
The Dowler family said: "We believe that they should know what Bellfield did to our beautiful daughter and sister Milly."
The schoolgirl was snatched by Bellfield, now 47, while walking from school to her home in Walton-on-Thames, Surrey, in March 2002.
He took her to his mother's house where he raped her. She was then taken to another location where the ordeal continued.
Bellfield didn't kill her until a day later when he strangled her to death.
Following a trial at the Old Bailey, Bellfield, who now calls himself Yusuf Rahim, was found guilty of abducting and murdering the teenager.
He was already in prison at the time for the murders of Amelie Delagrange, 22, and Marsha McDonnell, 19, and the attempted murder of 18-year-old Kate Sheedy.
Dowler’s body was discovered in woodland in Yateley Heath, Hampshire, 25 miles from her home. The cause of death could not be determined.
Bellfield's admission came after Surrey Police arrested a second man in connection to the abduction and rape of Dowler, however he was later released with no further action.
He was given a whole-life sentence in June 2011.