The accident happened at 8.40am in the Bangkok Yai's Thaphra district.
At the scene, police found a wrecked Nissan Sefiro car heading towards The Mall Thaphra with its engine missing, while a four-vehicle pile up lay in the opposite lane heading to the underpass towards the Charansanitwong Road. The Nissan driver Ekkachai Sansern, 21, sustained a broken leg.
The slain woman, Australian national Merisa Walts, 31, was a passenger in a taxi.
Two other people found in the same taxi were injured. They were 22-year-old Watcharaporn Hatkitnikorn who sustained a broken leg and taxi driver Wiroj Temboonborisut, 34, who suffered a neck injury.
About 30 metres away from the scene was a Honda, which was hit by the Nissan's engine.
The driver Nittaya Lomthong, 32, suffered abdominal injuries from the impact
Anusorn Niamlarp, 43, who was driving a Toyota pick-up truck involved in the pile-up, told police he was heading to the Thaphra underpass when the Nissan car coming in the opposite direction overtook several vehicles and then side-swiped his truck.
The Nissan car then crashed into a yellow-black taxi causing the engine to fly off and hit the Honda, he said.
The green taxi, with the slain passenger, in an attempt to avoid the Nissan, swirled to the left and rammed into a yellow-black taxi. Another taxi then slammed into the green taxi's rear, according Anusorn.