A man’s fragile sense of self was so shattered by a break-up that he brutally bludgeoned his ex to death inside the school where they both worked, an expert says.

Hockey coach Paul Thijssen hit water polo coach Lilie James in the head with a hammer at least 25 times inside St Andrew’s Cathedral School in Sydney on October 25, 2023.

James had ended her casual two-month relationship with the 24-year-old five days before she was killed inside the gym bathroom.

Forensic psychologist Katie Seidler theorised Thijssen killed his 21-year-old ex-girlfriend because he was terrified the break-up would unravel his facade of perfection.

She analysed Thijssen’s records and opined he had a fragile sense of self and saw himself as inadequate and unworthy, which led him to lie to create a flawless public image.

Although Thijssen wielded coercive control in his relationships, the psychologist said there were no obvious warning signs or indicators of violence.

Thijssen had no history of aggression and Seidler concluded there was probably nothing that could have been done to prevent the gender-based violence.

Issues of coercive control and unacceptable behaviour in relationships are being examined by an inquest into the deaths of James and Thijssen, who died hours after his ex-girlfriend.

Coroner Teresa O’Sullivan is assessing whether his death was self-inflicted.

Australia’s eSafety Commissioner Julie Inman Grant is set to give evidence on the final day of the inquest, before statements from James’ family are read out.

O’Sullivan has described the inquest as “an absolutely tragic case”.