NEW YORK -- In a case that provoked impassioned outcries from pet lovers, the owners of the Long Island Pet Cemetery were convicted of mail fraud yesterday for dumping thousands of dead dogs and cats in mass graves and bilking thousands of people who had paid for dignified burials for their pets.

The cemetery owners, Samuel J. Strauss, 71, and his son, Alan J. Strauss, 36, were each found guilty of 45 counts of mail fraud and are expected under federal sentencing guidelines to be sentenced to at least 6 1/2 years in prison, said Andrew J. Maloney, the U.S. attorney for the Eastern District of New York.

Government lawyers in the case displayed a succession of grisly photographs of pet carcasses dumped in pits and packed one atop the other in a crematory at the cemetery.

Lawyers for the Strausses said they would appeal the verdict.