Smithfield, N.C. — An emergency room physician, a State Bureau of Investigation agent and a former social worker testified Tuesday in the murder trial of a Johnston County woman accused of killing her 4-year-old adopted son.

Lynn Paddock, 47, is charged with murder in the Feb. 26, 2006, death of Sean Paddock. Investigators said Sean suffocated after she wrapped him tightly in a blanket to keep him from wandering around the house at night.

Defense attorneys insist the death was accidental, not punishment or discipline.

The six surviving Paddock children – five whom Lynn Paddock and her then-husband, Johnny Paddock, adopted and his daughter from an earlier marriage – testified over the past week that Lynn Paddock abused them almost daily for years. Children were beaten with a variety of objects, were forced to exercise or sit facing a wall for hours, were required to ask permission to use the bathroom and were denied contact with people outside the family, they said.

The abuse escalated as more children were adopted, reaching a peak after foster care workers placed Sean and his biological brother and sister with the family in 2005, the children said.

Dr. Benjamin Winter, an emergency room physician at Johnston Memorial Hospital, examined the four youngest Paddock children shortly after Sean's death and testified Tuesday that they had multiple bruises and other physical marks consistent with abuse.

"All the children said they were beaten by their mother with a whipping stick," Winter said.

Former social worker Heather Binder, who interviewed the Paddock children at the Johnston County Sheriff's Office, said she also noticed marks of abuse and signs of malnourishment in David Vorenkamp, Sean's biological brother who has since been adopted by another family.

"He was extremely thin, the thinnest I've ever seen a child," Binder said. "There was just no life behind his eyes. He seemed to be a very sad child. He seemed very withdrawn."

She said she called Johnny Paddock in to explain where the bruises came from.

"Mr. Paddock looked down at the marks, and he just became very emotional. (He) sort of hung his head, and he said, 'David, I am so sorry,'" she said.

Janie Pinkston Sutton, an SBI special agent, testified that she interviewed Jessy and Tami Paddock six weeks after Sean died and heard the same stories of abuse from them that they have told jurors in recent days. Jessy Paddock is Lynn Paddock's stepdaughter, while Tami Paddock is the oldest of the adopted children.

"I had not interviewed any children who had been in a home for that length of time that exposed them to that amount of and kind of abuse," Sutton said.

Jessy and Tami Paddock have been granted immunity from prosecution, since they were adults in the home at the time of Sean's death and during part of the abuse the children have described.