Senior Constable Colin David Randall was so frustrated a work transfer was refused that when he was left alone with his baby son for the first time, he punched him to death.
Then 37, he struck his 10-week-old baby Kye in the stomach with such force it "pulped" his liver, ruptured organs and bruised the boy's lower back.
For three-and-a-half years after killing his son he lied to his wife, medical staff and investigators, but his ruse came undone when he pleaded guilty to manslaughter last Friday.
After Kye died in hospital in June 2014, Randall pretended it was due to injuries caused when he had incorrectly performed CPR.
His story was that he had put Kye in a swing and set about vacuuming his home, only to find him limp and unresponsive.
And for a while Randall's wife Debbra Chambers believed him.
"For 18 solid months after Kye died, I was lied to, manipulated, deceived by the man who I was married to, believing Kye's death was a tragic accident somehow and all his father did was try and save him," she told Brisbane Supreme Court on Tuesday.
"I believed everything you said. I trusted you being my husband, my closest partner, the father of my children and a serving police officer."
What really happened between Randall and Kye was revealed in court as preparations were made to sentence him for manslaughter, following the plea that came one week before he was due to face trial charged with murder.
Crown prosecutor Phil McCarthy said the day had started much the same as any other.
The usual routines were undertaken until Ms Chambers popped out to nearby shops.
She left Randall alone with their boy for the first time, unaware of how frustrated he had become.
The court heard Randall, a former science teacher, had been having an affair with a police administrative worker from Hervey Bay and was fixated on moving his family there.
After making arrangements to relocate, his plans were dashed when police knocked back his transfer request.
This led to an act of extreme violence, in which he lashed out and killed his son.
"It's just an horrendous attack on a 10-week-old baby," Justice Peter Davis said.
It left the boy with severe internal injuries, from which he never recovered.
"The child went into cardiac arrest because of the trauma," Mr McCarthy said.
He was taken to hospital and for two-and-a-half hours unsuccessful attempts were made to resuscitate him.
Mr McCarthy told the court Randall should be given a sentence comparable to Heidi Strbak.
She was jailed five months ago for a minimum four years for killing her four-year-old son.
Randall remains suspended from the police force and is expected to be dismissed after being sentenced in the coming weeks.
Australian Associated Press
