Police are not treating the fire as suspicious.

警方认为这场火灾没有可疑之处。

《牛津词典》

The fire is of suspicious origin.

这场火灾起因可疑。

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The soldiers were trained to fire flares at anything suspicious; they went off all the time.

士兵在接受训练期间就学会了要随时向任何可疑的光亮处开火，而光亮总是稍纵即逝的。

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He said fire investigators had found a suspicious seat of fire near the lounge window at the back of the house, and smoke patterns suggested the windows were open when the fire broke out.

BBC: Fernhurst victim attacked before house fire

Investigators said there was a "suspicious seat of fire" near a window in the lounge at the rear of the house.

BBC: Fernhust fire death prompts murder investigation

At first the adjusters were understandably suspicious about the fire.

FORBES: Magazine Article