Three teenagers were arrested today in connection with the death of a mother killed after a firework was pushed through her mailbox, The Times of London reported.

The boys, 17 and 18, who are from Cornwall, U.K., are being held in custody after detectives searched Facebook for clues in the murder case.

Mary Fox, 59, mother of 9, was trapped in her bedroom after reportedly pushing her 17-year-old son, Raum, to safety through an upstairs window as flames engulfed the house.

The teenagers were arrested after reports suggested that locals had posted their names on the internet. "Some of the information has come via Facebook — indeed it is unusual these days for Facebook not to feature in a case such as this," a force spokesman told The Times of London.

The remnants of a fireworks were found behind the front door of the family's home.

Police say it was pushed through the mailbox and started the blaze.

Two 17-year-old boys and an 18-year-old man are awaiting interview at Launceston police station, Great Britain.

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