Thomas Daniel Nuckles maintains he did not molest a 4-year-old boy while he worked at a Roanoke County day care center.

But DNA evidence taken from a stain on the boy's underwear overwhelmingly points to Nuckles, and a judge convicted him Thursday morning of forcible sodomy.

Nuckles, 48, entered an Alford plea, which means he maintained his innocence but did not wish to risk a trial by jury. After hearing a summary of the evidence, Roanoke County Circuit Judge James Swanson found Nuckles guilty.

As part of the plea agreement, Roanoke County Commonwealth's Attorney Randy Leach dropped a charge of aggravated sexual battery. Nuckles faces a maximum possible punishment of life in prison at his May 24 sentencing.

His attorney, Joe Painter, said Thursday afternoon that the DNA evidence wasn't as cut and dried as it first might seem. An independent lab test conducted by the defense showed that the DNA didn't come from saliva or semen, he said.

"It could only be skin particles, and that could have come from anywhere," he said.

Yet state lab results stated that the odds were greater than a quadrillion to one that the DNA in the stain came from anyone other than Nuckles.

Asked about his client's decision to plead, Painter said, "We've gone over all the different options and this is the route he's taking."

Thursday afternoon, Leach summarized the evidence presented in court:

Nuckles was a teacher at Country Bear Day School on Starkey Road in early 2006. The boy, one of his students, told his mother one day that Nuckles had made a sexual threat toward him, but when the mother questioned Nuckles, he was able to give an innocuous explanation.

Then on April 19, as the boy's mother was driving her son home, he told her Nuckles had performed oral sex on him. She pulled over and questioned her son, who repeated what he'd said and made a gesture demonstrating what he said Nuckles had done.

The boy's mother took him home, separated and bagged his clothes, and called police the next day. DNA swabs were taken from the boy and from Nuckles. Roanoke County police detective Tricia Farris testified that Nuckles showed no surprise when he was told of the accusations and asked to consent to DNA testing, Leach said.

Country Bear placed Nuckles on leave as soon as staff learned of the allegations. Nuckles passed background checks before he was hired there, an administrator has said.

In August, Roanoke County police arrested Nuckles at his home in Shawsville.

At a preliminary hearing on Nov. 21, the boy, then 5, testified by closed circuit television. He repeated what he'd told his mother and police but couldn't provide specifics about where the molestation happened or whether anyone else was present.

During the hearing, the boy referred to Nuckles as a "bad person."

Painter said Nuckles has worked extensively as a teacher in public and private schools. "He has no criminal record and there have been no similar allegations made against him in the past," he said. "We'll be calling lots of witnesses" at the sentencing hearing, Painter said, including a psychologist who has done an evaluation of Nuckles.

Staff writer Laurence Hammack contributed to this report.