A father who stabbed his 4-year old son to death has been found not guilty because of mental incompetence.

Two days before he stabbed his four-year old son to death Dave Janzow posted an image of him with his two kids on Facebook.

“Unforgettable moments in a frog pond,” he wrote.

The image showing a fit, healthy father with his two sons was nothing out of the ordinary.

Just a regular dad with his kids. Nothing in it foretold how he would stab his son to death in his ute, how his wife, Julia would ring police in a state of panic saying she had concerns for her son’s welfare at 8.30am or that his father had taken him out in their car. No signs that he would murder him in a frenzy.

Nothing in this simple image foretells how four-year old Luca would die a violent and gruesome death and his father, who loved him, was charged with his murder and then ultimately found not guilty.

At the time it was simply a Facebook photo, like thousands of others we see when we scroll through.

“Unforgettable moments in a frog pond.”

“Unforgettable moments in a frog pond.” David Janzow with his two sons.

At the time it was unforgettable, but its now one of the last pictures ever taken of Luca Janzow.

Yesterday Luca’s father, David Janzow, 37, was found not guilty of his son’s murder after a judge found Janzow was “mentally incompetent” at the time of the killing.

The court heard during his trial that the then 36-year old landscaper from Adelaide had taken his son Luca out for a drive with the intent on killing him as he wanted to “save Luca from what was to come”.

Documents tendered to the court said Janzow was diagnosed with bipolar disorder and had a long history of depression.

The ABC reports that Janzow pulled up at a secluded location with a nice view of the Adelaide hills and stabbed his son. He then tried to stab himself in the neck before driving to police patrolling a traffic incident nearby and telling them “I need help, I’ve murdered my son.”


As paramedics treated Janzow he told them: “I’m a psychopath with mental health problems. I stabbed my son with a Leatherman [hunting knife]”.

The court heard that there was no history of domestic violence at the home of the family in Adelaide’s Eastern suburbs. After his arrest Janzow, who ran a landscaping company, was described by friends as “an everyday nice guy.”

Luca’s mum described him as having “a beautiful nature, kind, gentle, caring, happy, shy, tolerant, cheeky creative boy.”

The family a “regular family.”

In her victim impact statement tendered to the court yesterday a heartbroken Julia Trinne, who now lives interstate with the couple’s other son, said that she had no indication her husband was capable of what he did.

“Dave became acutely unwell in a short period of time with absolutely tragic consequences,” she said.

“There was no warning. There was no suggestion any of us were in danger.

“I loved Dave right up until this terrible tragedy. In most other circumstances I would’ve been by his side no matter what, I would’ve worn my wedding ring with pride until my last days but now I cannot.

“A living nightmare does not come close to what I have been going through.

“In time my hope is that this tragedy will bring understanding and awareness to mental health.

The court heard that Janzow told a psychiatrist after he was arrested: “I knew this was bad, but everyone would be better off. I knew murder was bad but I just had to get rid of us because there was no good bone in a psychopath.”

“I discovered that I was a psychopath and that [Luca] had the same qualities in him. At two, Luca had a night terror and screamed for five hours — I had night terrors and screaming fits as a child. No-one in society wants a psychopath and it is characteristic to take their own or others’ lives and I had those thoughts in the last week.”


In her statement yesterday Luca’s mother told the court how she was devastated by the murder of her  “cheeky, creative boy with the most incredible blue eyes, infectious smile and laugh”.

“I have found that the rollercoaster of grief works in mysterious and unpredictable ways,” she said.

“I can only write about the experiences and challenges I have had to date, who knows what the future brings.

“There is one thing for certain and that is I will grieve for Luca until my last breath.”

“At the young age of four, Luca had the inner wisdom of someone far beyond his years,” she said.

“A beautiful nature, kind, gentle, caring, happy, shy, tolerant, cheeky creative boy with the most incredible blue eyes, infectious smile and laugh.”

Ms Trinne said she would use her family’s tragedy to lobby for greater awareness and acceptance of the mentally unwell.

“I loved sharing my life with Dave (Janzow) and I envisaged us as always being together. Dave was a beautiful husband … and was a loving and caring Dad,” she said.

“He had been gentle, supportive, encouraging, adventurous, entrepreneurial and motivated man.”

“I wish I knew your Dad was so unwell. “ Julia Trinne said.

“I wish I knew your Dad was so unwell. “ she said ”I wish I had heard something that morning or that I had got out of bed just a little bit earlier than usual … to stand in-between you and at the very least to have held you in my arms as you left this world,” she said.


The Advertiser reports that in court Janzow wept as his former wife spoke how their family had fallen apart.

“The man I would have turned to, the man who would have held me, comforted me, in the devastating times was gone,” she said.

“The man who I would have been grieving with, the man I loved so dearly was the man who took my son’s life.

“My hopes are that this tragedy will help bring awareness, understanding, support and promotion to mental health and bring attention to the struggles people with mental health issues and their supporters face,” she said.

“This attention needs to translate into a greater awareness and understanding of what health professionals, families, friends and the community can do to make positive differences to people with mental illness and to people with mental health which can fluctuate from generally unwell to acutely well.”

“For people around them not to deny or be ashamed but rather accept it,” she said.

“Work together, talk about it and seek help when it is needed. There will be positive things that come out of this tragedy and I will make sure that happens.”

“I will always try to focus on the rainbows after the storms and I’d like to encourage other people to do the same.”

David Janzow was found not guilty by reason of mental incompetence. He was detained in a secure psychiatric facility, will now face a lifetime supervision order. Julia Trinne lives with the couple’s other son, Luca’s brother interstate.

For help: Lifeline 13 11 14. Kid’s Helpline: 1800 55 1800. DV and Sexual Abuse hotline 27/4: 1800 737 732