A Mississippi sheriff’s office is investigating what it describes as several threatening letters that have been placed in residents’ mailboxes.

WDAM in Hattiesburg reports that Covington County Sheriff Darrell Perkins sid that his investigators are analyzing several threatening letters.

Perkins said his office has five letters and knows of two other possible letters that are handwritten and were placed in mailboxes in north Covington County. One letter was also found in Smith County.

All of the letters appear to have come from the same person.

None of the letters came with envelopes and made vague threats, Perkins said.

The letters were found in the Gilmer area and Lilly Valley area in northeast Covington County.

Perkins said his office dealt with a similar set of letters left in mailboxes a couple of years ago. The office never determined who sent those letters.