After his wife spotted a stranger lurking in the front yard of their Melbourne home, Kristen Gascoyne chased the man down and put him in a choke hold.
He thought he could "put him to sleep" until police arrived, but 37-year-old Ahmet Gezer was unconscious and not breathing when officers got to Dandenong North.
They began CPR immediately but Mr Gezer could not be revived.
Mr Gascoyne, who held Mr Gezer in the choke hold for 14 minutes after he first fell unconscious, was arrested immediately after the fatal incident.
But police and prosecutors agree there is not enough evidence to support a conviction on any criminal charges he might face.
Mr Gascoyne admitted he had "managed to choke the gentleman out on the ground" after his wife told him of a suspicious man lurking in their neighbourhood on December 2, 2019.
Ashley Gascoyne first spotted Mr Gezer at a bus stop around the corner from their home as she drove to the gym just after 5am.
She became suspicious when he put his thumb out toward her in a hitch-hiking gesture. She drove past and did a U-turn, later telling police Mr Gezer again made the hitch-hiking gesture.
She did another U-turn and headed back toward her home "convinced the man was up to no good and that he may try and break into my home".
Ms Gascoyne saw Mr Gezer in her front yard and called her husband.
CCTV footage showed Mr Gezer spent 40 seconds in the family's front yard. Mr Gascoyne saw Mr Gezer walk out of the driveway and then pursued him along the street.
There was a physical altercation and Mr Gascoyne wrapped his right arm around Mr Gezer's neck and held him face-down on the ground.
"The evidence suggests that at this point in time, Mr Gezer lost consciousness," Victorian State Coroner John Cain said in findings handed down nearly three years to the day after the fatal incident.
"Although Mr Gezer was in an unconscious state, Mr Gascoyne continued to straddle him in this position for a further 14 minutes. Mr Gezer ceased breathing during this time."
Mr Gascoyne then removed the unconscious man's shoes so he could not run away.
In findings handed down days after the third anniversary of Mr Gezer's death, Judge Cain said he accepted the opinion of police and prosecutors about there being no reasonable prospect of a conviction on the basis of available evidence.
But he noted the case could be re-opened if new facts or circumstances arose.
"I have been careful not to compromise any potential future prosecution in the course of my investigation," Judge Cain said.