UPDATE 1-Thai police arrest two people in stock rumour probe

(Recasts, adds quotes, details of arrests)

BANGKOK, Nov 1 (Reuters) - Police in Thailand arrested two people on Sunday on suspicion of spreading rumours about the health of the country's 81-year-old king that triggered a slide in stock prices, police said.

The two were charged with "feeding untrue information through a computer system which undermined the security of the nation", said Capt. Suttichai Tienbhodhi of the Crime Suppression Division in Bangkok.

Thai stocks .SETI plunged a combined 7.2 percent on Oct. 14-15 as rumours circulated over the health of King Bhumibol Adulyadej, who has been in hospital for more than a month, before rebounding 3.5 percent the following day.

Teeranun Wipuchanin, a 43-year-old unemployed former stock trader arrested at Bangkok's Suvarnabhumi Airport, said she had translated a news story by U.S.-based financial news and data provider Bloomberg LP.

"What I've done was translating documents from foreign media Bloomberg," she told reporters after her arrest.

"I got it from Internet," she added. "Everybody on that day wanted to know what caused the market to fall. The stock market had already dropped and we did the translation in the evening."

It was not clear for whom she provided the translation.

Police also arrested Kata Pajajariyaponga, 35, an employee of Thai stock broker KT Zmico Securities.