LOS ANGELES, Calif. (KTLA) -- City officials are investigating the disappearance of 64 animals from six shelters over the past year.

Nearly 40 of the missing animals, mostly dogs, were housed at the North Central shelter on Lacy Street in Lincoln Heights, according to Brenda Barnette, general manager of the Animal Services Department.

Barnette told the Los Angeles Times that clerical errors may be partly to blame, but at least some of the animals "wrongly disappeared."

Additionally, many of the missing animals were considered "highly adoptable," according to Barnette.

This has officials worried that they may have been stolen and then sold.

The LAPD and the City Personnel Department began investigating the missing animals at the North Central Shelter in April.

They've taken several steps since then, including adding new locks and making some personnel changes.

It's not clear if any employees have been put on leave.

Mayor Antonio Villaraigosa's office confirms that the Animal Services Department has asked for help investigating the matter.