The bank is located on Rangsit-Nakhon Nayok Road in tambon Bung Yi Thow of Thanyaburi district.
A bank employee, who asked not to be named, said the robber wore a full-face white crash helmet, a black jacket, white gloves and black trousers. The robber approached a female teller and threatened her with a gun, prompting her to run away. He then climbed over the counter and grabbed banknotes which he shoved into a bag.
He fled on a Honda Scoopy-i with the Bangkok licence plate Jor Tor Yor (จตย) 309. The heist took only one minute, according to the employee.
The robber apparently chose the right moment to storm the bank as its security guard, Pol Sen Sgt Maj Sutat Sookchoey went to toilet at the back of the bank at that time.
“While I was in there I heard bank employees shout in panic ‘Here it comes. Here it comes'. I rushed out but it was too late. The bandit had fled.
“I then radioed Thanyaburi police station and asked them to intercept the thug but he managed to escape,” the officer said.
Police are checking footage from security cameras to track the suspect's escape route.