A 42-year-old jobless man who posed as a National Environment Agency officer with his gang of four – and robbed a family in Bukit Batok of more than S$110,000 (US$80,683) worth of valuables six years ago – was jailed four years and nine months on Tuesday.

A court in Singapore also ordered Khoo Wei Chyi to get six strokes of the cane, after he pleaded guilty to one count of robbery and one count of unlawful departure.

In 2010, Khoo Wei Chyi and four accomplices targeted a house on Pavilion Rise in Bukit Batok, as they had heard the owner was a 4D lottery boss who had a habit of keeping large amounts of cash there, Lianhe Zaobao (Singapore) reported.

At 12:50pm on September 22, 2010, when the 49-year-old female owner Ong Siew Hong returned home with her nine-year-old daughter, they saw Khoo, who was wearing a surgical mask and donning gloves, dispensing insecticide with a fogging machine outside their unit.

Khoo told Ong he was an inspection officer sent by the National Environment Agency to check for mosquitoes at her property.

The mother, who held her daughter’s hand, opened the door and led the way for Khoo. But she was shocked to see four other ‘inspectors’ storm in when she turned around.

Khoo and his accomplices revealed their true intent, pulling out a knife and demanding to know where the family safe was. The men then tied Ong, her daughter and a domestic worker up with cable ties, and sealed their mouths with duct tape.

They forced open two safe boxes – one in the master bedroom on the third floor and the other on the first floor – from which they took more than S$100,000 (US$73,344) in cash in different currencies and a Rolex watch. Khoo was said to have obtained S$18,000 of the stolen money.

About an hour later, Ong managed to free herself and reported the robbery to police.

Khoo had been due to attend court over the robbery in July 2011, but he left Singapore by illegal means to Batam, in Indonesia’s Riau Islands, a week before the hearing.

However, he was finally caught on April 18 this year – found to have overstayed and was repatriated to Singapore. His four accomplices have already been punished.