Many parents have told NBC 10 they feel clueless about where their teens are going online and who their teens are communicating with.

That's why the NBC 10 Investigators decided to give some parents an opportunity to check up on their children, and some were not happy with what they found.

Some people might consider it spying on their child, which is not something many parents want to do, but police and other experts say when it comes to the Internet, you need to know if your children are exposing themselves to danger.

What worries a group of Washington Township parents NBC 10 gathered is the accounts their children have on online journal, or blog, sites like MySpace.com. MySpace is an Internet site where teens think they're harmlessly posting their innermost thoughts and feelings to friends, but experts say they are unwittingly exposing themselves to pedophiles, stalkers and perverts.

Parents stood in line to have an expert look their children up online. They gave basic information about their child and an undercover computer crimes detective from Gloucester County did the rest.

"He lied about his age," one mother said.

Her son is 15, but on MySpace, he says he's 26, but there is little information on the page the detective found.

"Something to consider -- does he have another MySpace account?" the detective asked.

Most children online have multiple sites. For example, they could have two MySpace accounts, a Xanga account and a Facebook account. They may not want parents to see some of the sites.

So the mom called home.

"So the only account you have, you sure?" she asked her son over the phone. "Because I love you. That's why. You can either tell me or I can take it out of the computer. "

The online hunt continued and the detective was right. There was another account more difficult to find because the teen said he lived in Sewell, Ala. The site includes pictures of him and friends and a few unmentionable comments.

"A lot of kids post things online. They don't realize they are going to have to live with forever," Internet safety expert Parry Aftab said.

What anyone, even a child says online is like a tattoo. It's tough to get rid of and schools and employers are looking at Internet sites as part of their background checks.

One mother NBC 10 spoke to said her 12-year-old daughter promised to get rid of her MySpace account when her parents found she posted provocative pictures of herself in a bathing suit, but NBC 10 found two more accounts the mother said she did not know about. The site includes personal information and pictures of friends Mom doesn't know.

"This boy I don't know, that boy I don't know. She bold-faced lied to me and said, 'I'm not doing this anymore.' That's disheartening to me," the mother said.

"They don't realize they leave a trail of cyber breadcrumbs right to their door anytime they're online," Aftab said.

Studies show 24 to 30 percent of teenage girls admit to physically meeting strangers they met online. With boys, 14 percent do the same. Recent headlines prove sometimes they end up meeting dangerous predators.

NBC 10 found the MySpace account of a 13-year-old.

"One thing that's good is she took the initiative to set her profile as private. If I'm not an accepted friend of hers, I can't get to her profile," the detective said.

The only problem is she's posted a picture. The detective recommends she take it down.

"Photos are used to manipulate and put on naked bodies. They put horns on them," Aftab said.

Predators and online bullies can manipulate, copy and print pictures in an instant.

Another mother said her two teens had secret accounts listing themselves in Brazil. She said she deleted the accounts and installed software to monitor her teens. She's looking for other secret accounts.

"The only way they could is if they went to someone else's house," the mother said.

NBC 10 found nothing and she was relieved.

"That's a good story," the detective said.

"Set your rules. What are you comfortable with?" Aftab said.

You can teach your child to be safe on the Internet. That means talking about why it's important not to put anything online you wouldn't want a parent, a principal or a predator to see.

"A lot of parents don't want to be that fly on the wall, but they need to recognize they have to know," Aftab said.

NBC 10 helped 10 middle school parents investigate their children. Of those, five found at least one online journal belonging to their child of which they had no knowledge.

NBC 10 asked MySpace some questions about their practices. Click here to read their complete responses.

 Full Story and Parent Search Tips from NBC 10 here.