THE jury in an inquest that starts hearing evidence today on last year's killing of a Korean businessman and his hostage-taker is expected to visit the three key scenes during the siege. The inspection tour will go to Tsim Sha Tsui, Central and Pokfulam - all key sites in the gunman's rampage. It is understood about 50 witnesses will be called in the four-week hearing. Coroner Warner Banks has said he wants to hear evidence from a New Zealand tactical firearms expert and a chemist from the London Metropolitan Police. Chief Inspector Taffy Jones, head of the 8,000-strong special tactics group and armed offenders squad, will act as an independent source on the efficacy of police action in the fatal shooting of Cheung Cho-yau and his hostage, Kang Sang-bo, on October 14. Professor Bernard Knight is to give an assessment on the forensic material. It is understood four counsel will seek leave to appear at the inquest: one assisting the coroner, another lawyer for Kang's widow - who has won legal aid for the inquest - and one representative for an inspector involved in the shooting. The Police Commissioner's legal advocate is giving advice to junior officers. Cheung is alleged to have taken three hostages in a taxi last October after snatching an officer's gun. When cornered in Aberdeen, officers fired more than 20 shots in a gun battle. If an adverse finding is made, the Coroner can make a recommendation to the Attorney-General on the case for criminal charges. Two police were injured in their attempt to storm the taxi in which Cheung held the hostages. It emerged police ammunition was responsible for killing both Kang and Cheung.