Footage has emerged showing some of the last movements of those who died after a suspected cyanide poisoning at a Bangkok hotel.
The CCTV video, focusing on an internal courtyard, captures five of the six victims at the luxury Grand Hyatt Erawan hotel in Thailand.
It initially shows a man, one of the guests, jogging across the courtyard ahead of the others.
He is followed by four other members of the group, who go through the same doorway.
Two other men, who appear to be members of staff, carry deliveries to the same door as well.
The footage was taken on Monday, and shows some of their latest known movements on the same day they were last seen alive.
On Wednesday, local police said traces of cyanide had been found in cups and two teapots in the hotel room and that poisoning was the most likely cause of death.
The four Vietnamese nationals and two Vietnamese Americans were found by a hotel staff member in the room, which was locked from the inside.
Food had been ordered by room service, but it had been left untouched aside from the drinks which had been consumed.
Four of the bodies were found in the living room and two others in the bedroom.
Police said that two of the victims appeared to have tried to make it to the door, but collapsed and died.
Hotel records showed there were no other visitors to the room.
A police graphic of the crime scene showing where the bodies were discovered. Pic: Reuters
Uneaten meals in the hotel room. Pic: Royal Thai Police via AP
Police Lieutenant General Trairong Phiwpan, head of the Thai police force’s forensic division, told a news conference on Wednesday one of the six is believed to be the one who committed the murders.
“After staff brought teacups and two hot water bottles, milk and teapots… one of the six introduced cyanide,” he said.
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Interviews with relatives of the dead revealed there had been a dispute over debt, police added.
It was also said there could have been a conflict among the six regarding investments worth millions.
The three dead women have been named as 46-year-old Nguyen Thi Phuong, Sherine Chong, 56, and Nguyen Thi Phuong Lan, also 46.
The male victims are Tran Dinh Phu, 37, Dang Hung Van, 55, and 49-year-old Hong Thanh Pham.
The six were last seen alive when the meal was delivered to the room on Monday afternoon.
The Vietnamese government said its embassy in Bangkok was working with Thai authorities on the case, while the US State Department said it was monitoring the situation.