A tall Thai man ate out at a restaurant in Chalong, on Phuket's east coast, with a friend on Wednesday night. After he finished the meal, he told the waiter he did not have the money to pay for it and would be back.
According to Phuket police, the man then rode a motorcycle with his friend to Phuket's holiday west coast, where he tried to snatch the bag of Mrs Smith outside the Katathani Beach Resort in quiet Kata Noi, not far from Kata and Karon.
Mrs Smith, 60, would not let go so the man stabbed her in the heart. He left her bleeding to death in the street, with her wounded companion, another Australian travel agent, Tammee Lee, 42. His dinner bill remained unpaid.
Police brought the alleged killer, Surasak ''Boy'' Suwannachot, 26, and and his getaway motorcycle rider, Surin Taptong, 37, back to Phuket last night with the case rated so important that Thailand's top cop, Priewpan Damapong, travelled to Phuket.
Investigating officers praised the man from the restaurant who gave police the vital piece of information that led to the arrests of the two men yesterday.
''He saw television reports and realised how important the case was, so he walked to Chalong Police Station and told them everything he knew,'' an officer said.
''Without him coming forward, we would still be hunting the men. He has no interest in the 300,000 baht reward, he just wants to help Phuket recover its safe image.''
The two accused were expected to take part in a media presentation and a reenactment today. Last night General Priewpan visited Patong, Phuket's nightlife hub, to see for himself what the well-known Soi Bangla walking street is like.
Prime Minister Yingluck Shinawatra has promised a major overhaul in Phuket, Samui and Pattaya to wipe out rip-offs, jet-ski scams and overpriced taxis to make the destinations more appealing.