Police are describing the death of a four-year-old girl in Grimsby as "unexplained".
Poppy Widdison died at the weekend after being transferred from Grimsby to Sheffield Children's Hospital.
Two people have been arrested.
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Frosty, icy start on Sunday with fog patches lingering. In fact the fog patches may be very slow to lift in Lincolnshire
Widespread frost and patchy fog overnight
Wintry showers then frosty tonight, dry and cold on Sunday