(Reuters) - An Alabama mail carrier has been suspended and charged with aggravated animal cruelty for allegedly feeding meatballs laced with nails to at least one dog on her route, U.S. Postal Service officials said on Friday.

A joint investigation by the Madison County Sheriff’s Office and the U.S. Postal Service revealed that Susanna Burhans, a 47-year-old Postal Service worker, targeted a dog in a residential neighborhood in New Hope, Alabama, about 94 miles (151 km) north of Birmingham, said Postal Service spokeswoman Jeldrys Lowry.

The U.S. Postal Service Office of Inspector General opened an investigation into the case last month after Burhans was reported to be throwing contaminated food at a dog.

Officials have not given details on the condition of the dog but WHNT News reported its owner, Ed Glover, told the news station he found one of the nail-filled meatballs near the mailbox at his home and that when he took his dog, Missy, to a veterinarian, X-rays showed nails in its stomach.

“The USPS OIG considers the allegation to be a very serious matter,” Lowry said.

Burhans was arrested on Thursday and was released after posting $2,500 bail, according to media reports from AL.com, citing Madison County Sheriff Captain Mike Salomonsky.

Salomonsky did not immediately respond to a request for comment from Reuters. Burhans could not be reached for comment.

A veteran letter carrier, Burhans is currently on a non-duty status with the USPS, Lowry said.

A motive for Burhans’ actions was not immediately known. Court records from the arrest were not immediately available.