Mr Mischewski has pleaded not guilty.
Mr Mischewski has pleaded not guilty. John Weekes

Covert op overheard: 'I punched someone ... and they died'

A 'COVERT operative' allegedly heard Brandon John Mischewski confess to killing a homeless drug addict. 

Mr Mischewski pleaded not guilty on Wednesday to unlawful striking causing the death of Scott Frank Williams. 

He has also pleaded not guilty to the alternative charge of unlawfully killing Mr Williams, who died in Buddina in January 2016. 

Prosecutor Phil McCarthy claimed Mr Mischewski, after his arrest, told an undercover cop "I punched someone the other day and they died". 

Opening the Crown case, Mr McCarthy said Mr Williams was a homeless addict and "his prize possession was his car".

The prosecutor told Brisbane Supreme Court a dispute over money preceded the fatal incident at Buddina last year. 

"Frankie had got himself into some trouble - he had failed to repay a debt, and [Mr Mischewski] was somehow involved in that debt." 

He said jurors might hear from a witness who heard Mr Williams begging for the return of his car and "pleading that he will repay what he needs to". 

Mr McCarthy said Mr Williams died after suffering a "large fracture to the left side of his skull". 

Images of Mr Williams's lifeless body in the Buddina apartment were shown to the court and some members of the public gallery were upset.

Mr McCarthy said a witness saw Mr Williams on a couch "clutching his head in pain" with his eyes rolling back. 

She tried applying frozen food to help him with the pain, the prosecutor said. 

Mr McCarthy said that witness spoke of Mr Williams waking intermittently and then convulsing in a manner "like having a seizure". 

The trial continues. 

Justice Ann Lyons told jurors the trial was expected to last about six or seven days.