Cary, N.C. — More and more parents are buying nanny cams to babysit the babysitter. The cameras are discreet and available in many forms – from a clock to a can opener.

One of them was Cary mother Lindsay Addison, who bought a nanny cam when she went back to work from caring for her twin sons, Gavin and Bryce, and was shocked by what she saw on her computer screen.

Child advocate Karen McLeod said Friday that a nanny cam is a good tool. Parents should also check references and do a background check before hiring a nanny, though that part didn't avoid Addison's issues.

“Parents know. Parents have a really good sense and they should listen to their guts – and if something tells them something isn't right, they should definitely follow up on it,” McLeod said.

“I probably never would have suspected, never would have known, and she would still be here had I not had the camera,” Addison said. “And it scares me to think what could have happened to my children.”

Addison's boys were born early and had spent months in intensive care. Addison posted an online ad for a nanny because the twins still were not healthy enough to go to day care.

After interviewing six candidates, she hired someone she thought she could trust – a nanny who had a “glowing recommendation” from someone who had known her for 15 years.

The nanny started in early January. Last week, Addison installed a hidden camera she had purchased for $330 over the Internet. She said she wanted to check on whether the nanny was doing what Addison asked – and she missed her boys while at work.

"Quite frankly, I just wanted to see my children during the day after being with them for nearly seven months,” she said.

“At first, I didn’t see anything wrong,” Addison said. “And then, I logged back on a little later to check on them, and I started to see things I didn’t like."

She said she saw Gavin unattended on the couch and kicking. Later, she saw her other son fall from the nanny’s chest into the side of the couch.

Addison left work early, returned home, told the nanny what she had seen and fired her.

Police investigated but said the treatment did not rise to the level of being a crime, however.

The nanny, whose name and identity are being withheld because she has not been charged with a crime, had no comment and asked that she not be contacted again.