A mainland robber who allegedly targeted people driving luxury cars was nabbed by police in Tsim Sha Tsui yesterday. The 22-year-old, who arrived from the mainland last Thursday, was found with an air pistol and a knife when he was picked up in Canton Road at about 12.30pm. Police said the drivers of a Porsche, a Mercedes-Benz and a seven-seater Alphard were threatened with what appeared to be a pistol on three separate occasions on Hong Kong Island in the past four weeks. Most recently, at about 9.15am on Monday, a 54-year-old lawyer was robbed of HK$2,000 in his Porsche in the Rodney Street car park in Admiralty. At 1pm on Sunday, a woman in a Mercedes-Benz was stopped at a red light in Man Cheung Street, Central when a man threatened her with what appeared to be a pistol and tried to open her car door. On November 20, the Alphard driver was threatened with a similar object in the Rumsey Street car park at about 2.15pm.