Speaking outside court after sentencing in January 2024, Mr Coates' son James said Calocane had "got away with murder" while Mrs Webber said "true justice has not been served".
Ms O'Malley-Kumar and Mr Webber, both 19, and Mr Coates, 65, were stabbed to death by Valdo Calocane before he attempted to kill three other people in June 2023.
Calocane, who had been diagnosed with paranoid schizophrenia, was sentenced to an indefinite hospital order after prosecutors accepted a plea of manslaughter following the killings.
Read more:Three officers investigated over their inquiries into CalocaneSpecial constable sacked after viewing footage of dying victimsReview into decision to accept Calocane's manslaughter pleas.
"If any of them knew that Valdo Calocane was going to go out and share student accommodation with their children, I suspect their choices may have changed," she said.
