Clayton, Mo. ? A 39-year-old man serving six years in prison for possessing child pornography was charged Tuesday in a decade-old sex crime involving a child.

William “Alex” Field of St. Louis County was charged with kidnapping a 6-year-old girl from an address in Clayton, taking her into a garage, and sodomizing her. The girl is now 16 years old.

An investigation into the May 1997 crime had turned up no suspects, St. Louis County Prosecutor Robert McCulloch said. The case had been inactive until DNA tests pointed to Field.

Last year, Field began serving a six-year sentence at the state prison in Pacific for 12 counts of possessing child pornography. Those charges stemmed from a tip about suspicious behavior that led police to find the pornographic materials.

Inmates entering the prison system must submit to a swab of the inside of their cheek to gather cells containing DNA for comparison to open criminal cases.

Field’s DNA profile registered a match to the 1997 case, McCulloch said. A second test confirmed the same results.

McCulloch said he will alert authorities in a number of Midwestern states where Field traveled as a photographer. He took photos of children involved in sports and other activities for a photo-service business that catered to small communities.

Besides Missouri, Field worked in Indiana, Nebraska, Kansas, Oklahoma, Arkansas, Ohio and Illinois from the early 1990s until he was incarcerated last year.

Field faces one count of kidnapping and two counts of forcible sodomy.

With Field in prison, it’s unclear when the latest case against him will proceed, McCulloch said.