Lilie James was beaten to death inside St Andrew's Cathedral School in Sydney's city centre just before midnight on October 25, 2023.
The 21-year-old had days earlier ended a brief relationship with her killer, colleague Paul Thijssen, who is suspected of killing himself hours after she died.
An inquest into their deaths on Tuesday revealed the Dutch-born man's history of stalking Ms James and a prior partner, as well as a web of lies he spun about his time in Australia.
Those lies duped friends, housemates, his employer and, with numerous forged documents, Australian visa authorities.
After being dumped by Ms James, he set about stalking her and carefully planning her murder, the coroner heard.
In the hours before the murder, he "rehearsed the attack", counsel assisting Jennifer Single SC said.
"It was not a momentary loss of control - it was a premeditated killing," she said.
"The killing itself was overkill."
While the cause of both deaths was known, "the matters which led Paul to act the way he did are not", Ms Single said.
"It's important to understand what happened to Paul to understand what happened to Lilie," she said, pointing to the inquest's focus on preventing similar deaths.
The inquest will delve into broader issues such as coercive control and unacceptable behaviour in relationships.
NSW state coroner Teresa O'Sullivan will consider issues such as the role of technology in relationships and how to improve public understanding of ways to identify damaging behaviour in relationships.
The inquest will focus particularly on relationships between young adults, such as the one between Ms James and her ex-boyfriend.
The coroner will also attempt to determine whether authorities could have intervened at any point before the pair died.
Ms James's parents were in attendance for the opening day, although they are not represented by lawyers at the inquest.
The Thijssen family says it has evidence Paul's life had "become derailed" but that information has not been provided to the coroner.
In a colourful memorial service after her death, Ms James was remembered by her family as "vibrant, outgoing, and very much loved by her family and friends".
Sixty-four women were killed through violent acts in 2023, according to research group Counting Dead Women Australia.
Coercive control has been identified as a precursor to 97 per cent of intimate partner domestic violence homicides in NSW between 2000 and 2018.
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