National Centre for Missing and Exploited Children published a Parent’s guide to Internet Safety prepared from actual investigations involving child victims, as well as investigations where law enforcement officers posed as children.
Below listed are some of the signs that your child might be at risk online.
1. Your child spends large amounts of time on-line, especially at night.
2. You find pornography on your child’s computer.
3.Your child receives phone calls from men you don’t know or is making calls, sometimes long distance, to numbers you don’t recognize.
4.Your child receives mail, gifts, or packages from someone you don’t know.
5.Your child turns the computer monitor off or quickly changes the screen on the monitor when you come into the room.
6.Your child becomes withdrawn from the family.
7.Your child is using an on-line account belonging to someone else.
You can read the entire guide in http://www.fbi.gov/publications/pguide/pguidee.htm.