JEFFERSON COUNTY, Colo. (CBS4)– Authorities in Jefferson County are warning residents about a rash of mailbox thefts that resulted in fraudulent purchases.

The Jefferson County Sheriff’s Office says there have been thefts from mailboxes in Genesee and south Jeffco areas. Investigators want people living in those areas to check their personal information.

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On Oct. 15 stolen mail was discovered in the mountains by a work crew on a construction site. The bulk of the mail was from Park County but there was mail from residents in Jeffco.

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On Oct. 28 deputies investigated a cluster of mailboxes that had been burglarized. A week later, deputies received reports of a large number of locked mailboxes that had been burglarized. Investigators started receiving reports of victims’ personal information or financial information, like credit cards, checks and convenience checks being used in the Denver metro area.

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The Jeffco Sheriff’s Office reminds residents to check their mail regularly and to encourage people to pick up their checks at the bank rather than have them sent to their home. Also, ask banks and credit cards to stop sending convenience checks.