A boy and a girl, each 15, have been arrested on suspicion of the murder of 16-year Brianna Ghey.
Brianna, who was transgender, was stabbed to death in Linear Park, Culcheth, Cheshire, on Saturday 11 February.
Police are conducting a post mortem and are searching for the weapon used in her death.
They have also ordered a no-fly zone over the park, after drones were spotted flying over the murder scene.
They are seeking a motive for the attack. In an initial statement they said that they currently had no evidence that this was a hate crime. However, they are now revising that opinion.
A series of candlelit vigils is planned for this evening in Liverpool and Bristol.
Others are planned in Manchester, Glasgow, London and Brighton as well as other cities through the UK.
In a statement, Brianna’s family asked for privacy during “this extremely difficult time” and said: “Brianna was a much loved daughter, granddaughter, and baby sister. She was a larger-than-life character who would leave a lasting impression on all that met her. Brianna was beautiful, witty and hilarious. Brianna was strong, fearless and one of a kind.
“The loss of her young life has left a massive hole in our family, and we know that the teachers and her friends who were involved in her life will feel the same.”
A GoFundMe crowdfunding page set up for Brianna’s family, has already passed £67,000.