The Mongrel Mob wanted to track down Christchurch woman Mellory Manning because she owed them money, a court has been told.
Mauha Fawcett, 26, is charged with murdering the 27-year-old prostitute in December 2008 as part of his initiation to the gang. He is representing himself, although a lawyer is present to assist the court.
The Crown has told the court that Mr Fawcett knocked Ms Manning unconscious and took her to a gang property in the suburb of Avonside, where she was attacked by several men and killed before being dumped in the Avon River.
On Wednesday, the jury at the High Court in Christchurch was told the gang was trying to control the area around Manchester Street where Ms Manning worked.
A witness, who has name suppression and was screened off from the accused in court, said she spoke to Mauha Fawcett and another gang member on the night of the attack.
The woman said they asked if she knew where Mellory Manning was because they wanted to find her and get money off her. She told the men she didn't know where Ms Manning was and they left.
The Crown says Mauha Fawcett had begun charging prostitutes $20 for every job they did.
A previous witness has said Ms Manning tried to avoid the gang and didn't pay them.
Traces of drugs found in Manning
Forensic scientist Helen Poulson also gave evidence on Wednesday, and told the court she detected high levels of methadone in Mellory Manning's blood and liver.
Ms Manning was a recovering drug addict and part of a methadone programme.
Dr Poulson said there were also high levels of THC, the active ingredient in cannabis, which indicated recent use. She also detected low levels of morphine and diazepam, used to treat anxiety.
"It's not possible to determine, from the levels of these drugs in the blood, how Ms Manning was affected by them at the time of her death," Dr Poulson said. "There was no evidence for the use of alcohol or other drugs."
Earlier on Wednesday, the court was told that Mellory Manning last used her cell phone about 10.45pm the day she was killed.
A Vodafone radio frequency analyst said her whereabouts on the night of 18 December 2008 could roughly be tracked by knowing which cell phone towers it transmitted to.
Police officer David Parker said Ms Manning's last communication on her cell phone was about 10.45pm.