A gang of five mainland Chinese were arrested on Wednesday over preying on at least three Hongkongers wearing gold necklaces, who they lured with the promise of massages before making off with HK$80,000 (US$10,190) worth of jewellery in total over the past month.

Two women from the group were seen approaching a male passer-by near Heng Yuet House in Heng On Estate, Ma On Shan, at around 9am on Wednesday, prompting a witness to call police.

Officers later spotted and arrested the two women and their husbands, all aged between 51 and 54, inside the Heng On MTR station. The force covered their heads with black hoods to obscure their identities while they were escorted to a police van.

During questioning, the two couples admitted they had been involved in incidents in Aberdeen last month and Hung Hom on Tuesday, according to a police spokesman.

In the Aberdeen case, a 67-year-old man was robbed of his HK$25,000 necklace by two women in a staircase on Tung Sing Road before 3pm on March 4. The suspects said they wanted to befriend him.

In a similar incident on Tuesday in Hung Hom, an 89-year-old man was approached on Wuhu Street after 9am by two women who offered him a massage.

He was then taken to a staircase at the nearby Hung Wu Building, where the two suspects grabbed his genitals and stole his gold necklace worth HK$30,000.

The fifth suspect in the ring, a mainland woman aged 53, was arrested in Mong Kok on Wednesday afternoon for her alleged role in a similar robbery near the market in Heng On Estate on Tuesday evening.

The food market in Heng On, where a man was robbed of his necklace on Tuesday.

In the incident, two Mandarin-speaking women approached a 60-year-old man at about 6pm with an offer of a massage.

As they approached a staircase, the women grabbed the man’s genitals before snatching his necklace worth HK$25,000 and fleeing.

The suspects, all holders of two-way permits that allow mainlanders to travel to Hong Kong, were detained. The cases were handled by a Western district investigation team.

Apart from these cases, police also received reports of two other similar crimes on Wednesday.

A man in his 60s had his gold necklace worth more than HK$10,000 stolen by a sex worker in a guest house room on Shantung Street in Mong Kok at about noon.

In Sheung Shui, a man and a woman made off with a necklace worth HK$40,000 from a middle-aged man on Jockey Club Road before 2pm.