More than a dozen dead household pets, many of them frozen and euthanized, were reportedly found near Jacksonville, Fla., in the "worst" case of illegal dumping a sheriff has ever seen.

The remains, including that of two Labrador retrievers and a Shih Tzu, were found Thursday in two sites where carcasses had been recently dumped, The Florida Times-Union reports.

Baker County Sheriff Joey Dobson said the dead animals were left to rot in woods near a Baker County highway. Small and large trash bags found near Florida 121 South contained up to 15 dead animals with no obvious injuries and appeared to have been put to sleep, said Dobson, who called the case the "worst" he's ever seen.

Investigators were contacted local animal shelters near Jacksonsville to develop more information, The Florida Times-Union reports.

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