BANGOR – Within minutes after being sentenced to 16 years in federal prison for child pornography convictions, Maine’s former top drug prosecutor began his appeal.

During a 3½-hour hearing Thursday in U.S. District Court, James M. Cameron, 48, formerly of Hallowell and Rome, was sentenced on 13 charges of possessing and transmitting child pornography.

“Mr. Cameron, the question remains why. Why did you engage in this unlawful conduct?” U.S. District Judge John A. Woodcock asked him. “Mr. Cameron, you had so much to lose, and now you’ve lost it. … Today you’re not on the right side of the courtroom, prosecuting the criminals, but in the defendant’s seat, a criminal yourself.”

Cameron was convicted Aug. 23 after a six-day, jury-waived trial in federal court in Portland. He has been held by the U.S. Marshals Service in the Cumberland County Jail.

Woodcock ordered that Cameron serve 10 years of supervised release after his prison term, and that he register as a sex offender and be subject to a computer and Internet monitoring program.

The judge issued an order for Cameron to remain in Maine for two days so he can meet with an attorney to prepare appeals.

“Mr. Cameron will appeal the length of the sentence and the reasonableness of the sentence, as well as a selection of issues he raised prior to trial,” said his attorney, Michael Cunniff. “We will ask the 1st Circuit Court of Appeals to review the decision-making.”

Cameron entered the courtroom Thursday with his hands bound behind him in handcuffs. His legs were shackled. His hair was longer, shaggier and grayer than it was during his 18 years as an assistant attorney general.

Cameron appeared thinner, too, clutching the rear waistband of his green trousers to keep them from falling when he stood before the judge. He had no belt.

Woodcock and the prosecutor, Assistant U.S. Attorney Gail Fisk Malone, spoke of Cameron breaching Mainers’ trust.

In arguing that Cameron be sentenced to 22 to 27 years in prison, Malone said Cameron was “thumbing his nose” at Mainers when he viewed and traded child pornography while he was supposed to be working for the state.

“The defendant essentially committed this crime on the backs of the taxpayers,” Malone said. “In addition to breaking the law, he was cheating the state of Maine of the honest service he was paid to provide.”

In a brief statement before he was sentenced, Cameron apologized for causing his family and his colleagues pain and distress.

“I am here because of my own actions,” he said. “I am deeply ashamed of myself, and I offer no excuses.”

He also said he was “sorry for all victims of child sexual abuse.”

Cunniff had asked the judge to stick to the minimum prison term called for under the law — five years. He said prosecutors had indicated previously that they would recommend a sentence of 78 to 91 months if Cameron pleaded guilty.

Cunniff cited some reasons why Cameron got involved in child pornography over the Internet: “stress, distress, anxiety, the progressive deterioration and death of each of his parents, caring for (an ailing) family member, the pressure of his job and of a book he was writing, as well as a lifelong problem with obsessive-compulsive disorder and changes in medication.”

Cunniff maintained that a very low percentage of the images found on the four computers that Cameron used were child pornography.

Woodcock said he found it particularly “jarring” that images of 10- and 12-year-old girls clothed and posing next to monuments — images he said would be found in most family albums — were juxtaposed with images of naked girls of the same age involved in sex acts and exposing themselves.

“I reviewed those images until I was sick,” Woodcock said.

Cameron came under investigation after the National Center for Missing and Exploited Children reported that Yahoo! had found multiple images of child pornography in a Yahoo! account. A search on Dec. 21, 2007, revealed child pornography on a computer in Cameron’s home in Hallowell.

Cameron was fired as an assistant attorney general in April 2008, and was indicted on child pornography charges on Feb. 11, 2009. The indictment says the offenses occurred from July 10, 2006, to Dec. 21, 2007.

Cameron is losing his licenses to practice law in Michigan and Maine, he has gotten divorced, and he has run a failing Internet business selling watches.

Woodcock declined to impose a fine on Cameron, saying he has no ability to pay. More than a dozen people watched the sentencing.

At the beginning of the hearing, Woodcock noted that he had presided over the trial, read hundreds of pages of documents filed in connection with the sentencing, and ruled on dozens of motions in the case.

“There is a time for argument and a time for decision,” he said. “This is the day for decision.”