The parents of Martin Lee Anderson and three other families are filing complaints against Bay County medical examiner Dr. Charles Siebert and his autopsy findings on their loved ones.

Siebert performed the first autopsy on Anderson, a 14-year-old boy who died Jan. 6, a day after being hit, restrained and kneed by guards at the Bay County juvenile boot camp. The incident was captured on video. Siebert found that the boy died from sickle cell trait, or natural causesDr. Vernard Adams, the Hillsborough County medical examiner, performed a second autopsy, which found that Anderson suffocated after guards forced ammonia into his nose and covered his mouth.

Gina Jones, Anderson's mother, said Siebert should be fired and arrested. Jones and Anderson's father, Robert Anderson, along with other families, spoke out Thursday during a news conference at the law offices of Benjamin Crump and Daryl Parks of Tallahassee.

"What really happened to my baby?" Jones asked. "We all know. We've all seen the video."

Siebert, in a written statement, said he stands by his conclusions, which he said are "based on medical and forensic evidence." He remains on the job.

Also criticizing Siebert were Mary Francis Terry, who said autopsies on her husband and daughter were botched; Michaela Mahoney, who said her son's death was wrongly ruled a suicide; and John Niesen, who says his brother was beaten to death nearly 30 years ago despite a finding that he died from traffic-crash injuries.

Crump said he is helping Mahoney and Niesen file complaints with the Florida Agency for Health Care Administration, which oversees medical examiners. Anderson's parents and Terry already have filed complaints, he said. They're also calling on the Medical Examiners Commission to review the cases.

Siebert, in his statement, said the filing of complaints was not justified.

"My medical opinion may not be popular, but it is my job to issue conclusions rooted in scientific fact," he said, referring to the Anderson case. "While Dr. Adams has released his conclusion, which differs from mine, he has not released any medical or scientific evidence supporting his conclusion that would justify the family's quest to invalidate my original autopsy report."

No arrests have been made in the Anderson case. Gov. Jeb Bush appointed State Attorney Mark Ober to investigate the death. Bush said Thursday he expects "a lot more action" once Ober's investigation is complete.

"That is taking quite a long time, but he's deliberately, thoughtfully going through it," Bush said.