Heather Hyndman is hoping for answers as to exactly how and why her daughter, Chelsea, died in Crete.
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The men, all aged 19, were arrested on Tuesday.
Zena Victoria Jackson, 43, and her six-year-old daughter Cidalia Mendes-Jackson died after being hit by a lorry on Spring Bank in April.
Andrew Broadhead, 42, and his eight-year-old daughter Kiera died in the blaze at their home in Stanley in October.