Jonty Bravery pushed a six-year-old boy off the 10th-floor viewing platform at the Tate Modern, London last August.
The BBC and The Daily Mail acquired an audio recording of Bravery telling his care workers he planned to push someone off a high building.
Bravery has autism and was under the care of Hammersmith and Fulham council. A care worker recorded a conversation they had in 2018.
According to the BBC, in the recording Bravery says: “In the next few months I’ve got it in my head I’ve got to kill somebody.”
He then tells his carer: “It could be the Shard, it could be anything just as long as it’s a high thing and we can go up and visit it and then push somebody off it and I know for a fact they’ll die from falling from a hundred feet.”
The care worker claims to have told a senior member of staff about his conversation with Bravery. His specialist care provider Spencer & Arlington say they had “no knowledge and no records” of this alleged disclosure.
Bravery, 18, will be sentenced this month after admitting attempted murder at The Old Bailey.