A pub chef accused of murdering his ex-partner confessed to an undercover police officer, a court has heard.
Darren Osment allegedly killed Claire Holland, 32, in a drunken argument hours after she was last seen leaving a pub in central Bristol in June 2012.
The 41-year-old reportedly told an officer Ms Holland was not "going to be seeing the light of day again", Bristol Crown Court heard.
Despite police investigations, the mother-of-four has never been found.
The defendant, of Chessel Drive, Patchway, South Gloucestershire, has pleaded not guilty to Ms Holland's murder between 5 June and 8 June.
The jury heard when Mr Osment came under suspicion detectives deployed an undercover officer to befriend him.
Between December 2020 and July 2022, the officer posed as a man called Paddy O'Hara.
The jury was told he pretended to be involved in the criminal underworld with links to organised crime, and enlisted the help of Mr Osment.
Giving evidence from behind a screen, Mr O'Hara told the jury Mr Osment never spoke about Ms Holland in a positive way.
"He spoke about her in a very derogatory way. He would be quite abusive," he said.
"He referred to her as being toxic and a devil. He never referred to her by name."
Mr O'Hara said when Mr Osment spoke about her he often gagged or had to vomit, and said when he tried to sleep at night he could see her face and "black eyes".
The jury was played undercover recordings in which he discussed what evidence detectives might have against him after he was arrested in March 2022 on suspicion of Ms Holland's murder.
Mr O'Hara said: "He would talk about the lack of proof or evidence that could be got - that last piece of the jigsaw, referring to the body.
"He went on to explain that what he had done was probably wrong but what was done was done.
"He spoke to me on many occasions about killing witnesses who gave statements against him."
The jury heard Mr O'Hara give examples of Mr Osment losing his temper almost daily.
On one occasion, he witnessed him "kicking and stamping" on his dog after it tried to get into the back of a van, instead of the front.
The undercover officer also saw Mr Osment be verbally aggressive to his mother, and talk aggressively about a social worker involved with his family.
"He wanted to kill her. He wanted to kill her in front of her children, set her on fire," Mr O'Hara said.
Darren Osment reportedly blamed his ex-partner for their child being taken into care.
The court has heard he and Ms Holland, who were both alcoholics, met in 2008, with a child being born in 2010 after she drank through the pregnancy.
Mr Osment told Mr O'Hara how he had assaulted Ms Holland after coming home from work to find her drunk looking after their child.
In a recording, Mr Osment said: "Who drinks three bottles of wine when they're looking after a baby? She would have fallen down the stairs and killed [the child]."
The trial continues.