The police investigation into the disappearance of Alice Gross became a murder inquiry after her body was discovered on Tuesday night.
Alice’s parents, Rosalind Hodgkiss and Jose Gross, said after the discovery they had been left “completely devastated” by recent events.
“Why anyone would want to hurt her is something that we are struggling to come to terms with,” they added.
“Alice was a loving and much-loved daughter and sister, a quirky live spark of a girl, beautiful inside and out.
“She was a funny companion, a loyal friend, both passionate and compassionate, and so talented, with a bright future ahead of her. She brought so much joy to our family and those who knew her.
“We still don’t know who is responsible for this crime and we ask that people continue to help the police by giving them information that could help bring the perpetrator to justice.
The Metropolitan Police has come under fire for delays in identifying Zalkalns as a suspect, and have so far have not been able to apply for a European Arrest Warrant due to lack of evidence.
Metropolitan Police Commander Graham McNulty said “significant efforts” were made to hide the body, which was found near Alice’s family home in Hanwell, west London.
The River Brent runs a short distance from Hanwell and the towpath next to the Grand Union Canal where Alice was last seen on CCTV.