Cyanide used to kill Vietnamese, US citizens in Bangkok: Thai forensic experts

Thai forensic experts have established that six people found dead in a Bangkok hotel on Tuesday, including four Vietnamese and two U.S. nationals, had ingested cyanide mixed with tea.

The victims' lips and nails had turned dark purple, indicating a lack of oxygen, while their internal organs had turned "blood red", which is another sign of cyanide poisoning, said doctors at Chulalongkorn Hospital on Wednesday, adding that further tests are underway.

They also noted that a series of samples found at the scene included tea bags suspected of containing large amounts of cyanide. Brewed tea leaves are usually light brown in color, but the specimens found at the scene were dark, leading experts to believe they were laced with a large amount of cyanide.

Cyanide was found in the blood of all six people, according to the experts.

Based on the initial post-mortem examination, they stated that cyanide poisoning was the only possible explanation for their deaths.

The cyanide was found in used drinking glasses and water bottles in room 502 at the luxury Grand Hyatt Erawan Bangkok, where the bodies were discovered on Tuesday.

Police suspect that after hotel staff brought the glasses, two bottles of hot water, milk, and a pot of tea to the room, one of the six had added cyanide to the drinks.

They believe that one person was responsible for the incident, who then took her own life. The motive is thought to have stemmed from debt-related issues.

Two of the deceased were identified as Sherine Chong, 56, and Dang Hung Van, 55, both carrying U.S. passports. Chong was identified as the culprit.

The four Vietnamese nationals have been named as Nguyen Thi Phuong Lan, 47; Pham Hong Thanh, 49; Tran Dinh Phu, 37; and Nguyen Thi Phuong, 46.