Chilling CCTV shows six guests arriving at Bangkok hotel hours before cyanide poisoning

A chilling CCTV footage has emerged showing six guests arriving at a luxury hotel in Bangkok, just hours before they were all found dead in what is suspected to be a case of poisoning .

The bodies of two Vietnamese Americans and four Vietnamese people were discovered by a housekeeper on Tuesday night at the Grand Hyatt Erawan in Bangkok when the group failed to check out as scheduled.

Cyanide was detected in the blood samples of all six victims. Thai police believe one of them poisoned the others over a bad investment, but have not disclosed which one is the suspect.

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The deceased have been identified as Vietnamese nationals Thi Nguyen Phuong, 46, her husband Hong Pham Thanh, 49, Thi Nguyen Phuong Lan, 47, and Dinh Tran Phu, 37.

American citizens Sherine Chong, 56, and Dang Hung Van, 55, were also among the fatalities, reports the Express US .

Authorities revealed that a couple among the deceased had invested approximately $278,000 with two other members of the group to construct a hospital in Japan , and the meeting might have been arranged to resolve this issue.

Security footage captured the guests checking into the hotel with their luggage on Monday. The last sighting of the group alive was when room service delivered food on Monday afternoon. Hotel staff reportedly saw one woman receive the food, and security footage showed the rest of the group arriving later.

A housekeeper discovered the bodies on Tuesday afternoon. The food ordered on Monday was found untouched, but several used cups were present on a table.

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Police confirmed that traces of cyanide were found in the cups and thermoses. Preliminary autopsy results revealed cyanide in the blood of all six victims, according to police. Two bodies seemed to have attempted to reach for the door but collapsed before they could.

Authorities dismissed the possibility of a mass suicide as some of them had future parts of their trip planned, like hiring guides and drivers.

US State Department spokesperson Matthew Miller stated that the United States is keeping a close eye on the situation and extended his condolences to the families of the victims.