A man accused of trying to stab another man to death allegedly tried to destroy evidence by dousing the victim's bloodstains with bleach, a court has heard.
Forensic officer Melissa Bell said she had found blood on the kitchen walls and floor of a unit in Stafford, in Brisbane's north.
But she could not analyse much of the blood because it had been diluted with bleach, she told the Supreme Court in Brisbane on Thursday.
The court has previously heard the fingerprints of Neil Alan Simpson, who is currently on trial for the attempted murder of Patrick Fein, were found on a bleach bottle under the sink at the unit.
His co-accused, Toni Marie Prestidge, has allegedly told police she saw Simpson splash bleach around the kitchen in an attempt to destroy DNA evidence.
Both Prestidge and Simpson have pleaded not guilty to attempted murder.
Prestidge claims Simpson forced her to lure Mr Fein, 48, to the home and then repeatedly beat and stab him, cutting his throat with a shard of glass.
Simpson claims he was not at the unit when the attack took place in January last year.
The court heard Mr Fein suffered life-threatening injuries during the attack and had to undergo surgery.
The trial continues.