THE last witness has begun his evidence in the murder trial of Ballarat man Darren Wilson. Police informant and Homicide Squad Detective Senior Constable Dustin Shepherd is expected to be cross-examined by Wilson’s defence counsel for most of Friday. Wilson is standing trial in the Supreme Court having pleaded not guilty to the murder of Scarsdale teenager Timothy O’Brien,14. Now in its fifth week, the trial has heard from about 50 witnesses. Detective Senior Constable Shepherd told the jury he became involved in the case on January 5, adding he arrested Wilson and another man that afternoon. The jury has seen Wilson’s record of interview in which he tells the detective that he played no part in Timothy’s death. Detective Senior Constable Shepherd reads Wilson his rights and cautions him several times throughout the interview, with Wilson telling the detective he had already sought legal advice from Ballarat solicitor Mike Wardell. Timothy’s body was found at a Scarsdale house on the morning of January 5 last year. The jury has heard Wilson and a 16-year-old girl living at the house devised a plan to lure Timothy’s stepfather, Peter Williams, to the house and bash him. Mr Williams was jumped by Wilson when he arrived at the Scarsdale house in the early hours of January 5.&nbsp; Timothy used a baseball bat to defend his stepfather before he was allegedly chased out of the house by another man who allegedly used the blunt side of an axe to hit Timothy in the head. Wilson is accused of then grabbing the axe, turning it to its bladed side, and continuing to strike Timothy. Wilson is also charged with four counts of inciting others to murder witnesses. Two former prisoners who were on remand with Wilson last year have told the jury Wilson allegedly asked them to murder key witnesses. The trial before Justice Betty King continues.