Valdo Calocane has admitted killing three people who died in attacks in Nottingham on 13 June 2023.
Students Barnaby Webber, 19, Grace O’Malley-Kumar, 19, and school caretaker Ian Coates, 65, died after being stabbed in the city centre on 13 June.
The charged man, also known as Adam Mendes, denied murder but admitted three counts of manslaughter on the grounds of diminished responsibility at Nottingham Crown Court.
The 32-year-old also admitted the attempted murder of three others.
Prosecutors will review medical evidence before coming to a decision on whether to accept the pleas.
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