The parents of Leah Croucher have visited the house where police searching for her found human remains along with her rucksack and other personal items.
A message with the flowers laid by Claire and John Croucher said they would "cherish her memories forever".
It said: "Our darkest fears have come true, we only need to be apart a little longer. We have so missed you for so long already.
"The future looks so bleak now we know we will never see your smile or hear your laughter again. We will cherish your memories forever. We love you. Mum and Dad xx xx".
Forensic experts are still at the house and blue tarpaulin remains in the back garden of the house in Loxbeare Drive, Furzton, Milton Keynes. Detectives have put up a tent in front of the house and a tall black screen shields the scene from the street.
The search for Ms Croucher, who vanished in 2019, is focusing on a house less than half a mile from where she was last seen.
Her grandparents left yellow roses near the house with a handwritten note saying: "Our darling, we will never stop seeking answers. Will love and miss you always."
Other mourners laid a large wreath of white lilies and pink roses. A bunch of yellow, pink and red roses addressed to "our beautiful darling" had a note which said: "While our hopes and dreams to find you safe and well have been stolen from us a new hope for answers and justice is now part of our path to fight ahead.
"We promise you with all our hearts that we will never ever give up fighting for you. All our love always and forever."
On Wednesday Thames Valley Police said that they had found human remains at the property and investigators would be there for some time.
A police spokesman said: "Monday was the first time we were alerted to this property by a member of the public in connection with this investigation.
"However, as an address in Furzton, the address was visited as part of our house-to-house inquiries as part of the investigation, during which we visited more than 4,000 addresses.
"There was no response at the property and as such leaflets would have been dropped through the letterbox."
Ms Croucher was last seen on CCTV in Buzzacott Lane, Furzton, just after 8.15am on 15 February 2019 as she walked towards Loxbeare Drive and Chaffron Way on her way to work at a finance company.
Hundreds of officers have search for Ms Croucher over the past three and a half years. They have scoured 1,200 hours of CCTV and carried out 4,000 house-to-house inquiries.
Ms Croucher's parents have previously described the disappearance of their "beautiful and wonderful daughter" as "highly unusual", adding: "We still have no answers as to why."
(c) Sky News 2022: Leah Croucher's parents lay flowers at house where remains were found
