A federal judge in Connecticut has sentenced a professional photographer to more than 16 years in prison for turning a teenage girl into what prosecutors called a sex slave.

Judge Alfred Covello in Hartford called the case "terribly tragic" as he sentenced 61-year-old Robert Gamble of Clinton on Wednesday.

Authorities say Gamble sexually abused, assaulted and exploited the girl for five years beginning when she was 13. They say he took sexually explicit photographs of her and abused her during so-called sex lessons almost daily.

Gamble pleaded guilty to a child pornography charge. His lawyer says he plans to appeal.

The victim, now 21, told the judge on Wednesday that the abuse left her with lasting emotional problems.