A Hong Kong student charged with possessing petrol bombs near a police station last year has alleged he was set up by an officer who planted the weapons on him so that the force could make a sham arrest.

Lawyers for defendant Lam Wai-ho told West Kowloon Court on Thursday that Sergeant So Chi-hang had instructed a middleman to hire someone to carry out the crime outside Kwai Chung Police Station on April 13 last year.

Prosecutors said Lam, a 23-year-old student from the Hong Kong Institute of Vocational Education, knowingly took the petrol bombs to Kwai Chung Estate that night to prepare for an attack on the station on the opposite side of the road.

Lam Wai-ho at West Kowloon Court on Thursday. He has denied a count of possessing offensive weapons in a public place.

In the trial that began on Wednesday, Lam denied a count of possessing offensive weapons in a public place. His counsel, Albert Luk Wai-hung, said his client had been set up by the sergeant.

The court heard that So and three other officers were patrolling the housing estate when Lam put down a bag with the firebombs outside Kwai Ching House at about 8.50pm. The student was immediately intercepted and arrested.

Under caution, Lam claimed he had been told by a man with a tattoo on his arm that the glass bottles were red wine, and that he would be given HK$5,000 (US$643) if he took them to the estate for collection by a third party. The man did not reveal the recipient’s identity to Lam.

Policewoman Yiu Suet-ying gives evidence at West Kowloon Court on Thursday.

A week after the incident, So was arrested on suspicion of perverting the course of justice and suspended. He was not charged and the court was told he had recently resumed duty.

Two of the three officers who had patrolled alongside So testified on Thursday that he had acted alone elsewhere during most of the operation, but returned almost immediately after Lam’s arrest.

Policewoman Yiu Suet-ying and Constable Au Ho-ki both insisted the timing of So’s return was purely coincidental. Yiu denied knowing in advance the defendant would appear on the scene.

Constable Au Ho-ki.

Detective Constable Yiu Ka-yui, who investigated Lam’s case, said the man with a tattoo claimed in a police interview that he had learned how to produce petrol bombs and hired Lam under the instruction of a “Lik Sir” for a HK$3,000 reward. The man was not charged.

Both Yiu Suet-ying and Au denied knowing whether So used that nickname, saying they only referred to him as “Brother So”.

Luk, the defence counsel, said he would call So and Kelvin Leung, the inspector in charge of the case, to give evidence in the coming sittings. The trial continues before Magistrate Minnie Wat Lai-man on Friday.