SACRAMENTO, Calif. -- Animal autopsies have been conducted on nine dead cats in an ongoing animal neglect investigation that may result in criminal charges against a Sacramento man and his mother, officials said Friday.

About dead 278 cats, six dogs and four fish were found in several freezers in a south Sacramento home last month.

The cause of death is still under investigation, but many of the pets appeared emaciated.

Sacramento's Animal Care Services performed the pet autopsies, known as necropsies.

Michael VonDueren was arrested last month on suspicion of obstructing police and possessing an illegal AK-47 in his home, police said.

During the arrest, police found 30 live cats wandering around and dead animals stuffed inside three separate freezers.

Authorities said VonDueren and his mother, Elaine Parnell, may face misdemeanor charges of possible animal cruelty or neglect.

The case will be forwarded to the District Attorney's Office.