Police have arrested a 40-year-old man just eight hours after he allegedly robbed a convenience store in Hung Shui Kiu at knife point and stole a taxi in the early hours of Friday morning.

Inspector Lam Ho-yin of the force’s Yuen Long district crime squad said the suspect allegedly concealed his face and upper body using a black garbage bag before showing up at the shop at around 2am and producing a knife about 20cm (7.87 inches) long.

“The man threatened the female cashier with a knife and declared a robbery. Feeling frightened, the cashier handed over HK$1,550 [US$197] in cash from the register and, as demanded by the man, seven packs of cigarettes,” he said.

Lam said the man then immediately headed to the nearby Hung Shui Kiu Light Rail station, where he intercepted a taxi and instructed the male driver to take him in the direction of Yuen Long.

“Upon reaching the Long Tin Road area, the suspect suddenly pointed the knife at the driver and ordered him out of the vehicle. Then the man drove away with the taxi,” he said.

The inspector added that the suspect allegedly took a mobile phone, a tablet computer, a towel and HK$3,400 in cash from the cabby.