Accused murderer Bradley Scott Purkiss took on a father role to his alleged victim's son, a court has heard.
Mr Purkiss is facing trial in the Hobart Supreme Court alongside Margaret Anne Otto for the murder of Ms Otto's husband Dwayne Robert Davies.
The pair have pleaded not guilty.
Mr Purkiss was the last person to see Mr Davies on May 26, 2017, and his body was found a week later at Levendale.
In an interview with police on May 30, 2017, Ms Otto said the relationship between Mr Davies and their son Brady had been not so good in the last 12 months.
A video of the interview was played for the jury.
"Brad filled a little bit of that void," Ms Otto said in the video.
"[Dwayne's] behaviour over the past 12 to 18 months has been extremely erratic.
"The reason [Brad] got so frustrated with Dwayne was because his actions were affecting Brady."
MORE FROM THE TRIAL:
- Wife and best friend stand trial for tattooist's murder
- Tattooist killed in cannabis grow shed, court hears
- Accused told employer it would be easier if her husband was dead
- Victim sought firearms for friend in weeks before his murder
- Alleged killer's partner was trying to leave relationship
- Accused murderer used to shoot at Levendale
- Court hears of physical altercation before alleged murder victim was last seen
Ms Otto told police on the night Mr Davies disappeared she had last seen him at 6pm when he left their Risdon Vale home in her car.
She said she finished a cake for her grandson's birthday party the next day before falling asleep while reading.
Ms Otto said when she woke up at 10.45pm and saw her husband was not home, but her car had been returned and Mr Davies' keys and phone were at the house, she "had an overwhelming feeling something wasn't right."
"He's usually in bed by then," Ms Otto said.
Ms Otto said her worry "got the better" of her and she got into her car and drove partway to Mr Purkiss' Elderslie residence, the last place she knew Mr Davies was.
"I'm three-quarters of the way out there and all of a sudden I've gone - it doesn't make sense," Ms Otto said.
"I felt like normally I was a logical, rational person and I didn't feel logical, rational or in control."
Ms Otto said she questioned if Mr Davies' absence was "one of his mind-games".
"Is this purely about trying to get my attention to see if I'm worried," she said.
MORE FROM THE TRIAL:
- Accused killer 'debt-free' after husband's disappearance
- Alleged murderer arranged last minute shooting trip to Levendale
- Dwayne Robert Davies 'obsessed' with television anti-hero Walter White
- Accused murderer attended birthday party for alleged victim's grandson
- Alleged killer confident police would find no evidence of foul play
- Accused told police he was being framed for best friend's murder
- Father of accused's information led police to grave site
Ms Otto told police she had considered leaving Mr Davies.
She said she had been working 60 hours a week and had been looking after her husband, who was often not able to work due to illness.
"I started to resent him and everything about him," Ms Otto said.
"Talking about it now, it's like, how the hell did I get here?
"I was in a disillusioned state that I could help him, save him."
The trial before Chief Justice Alan Blow continues.