Summarize this article in one sentence.
As an adult in your household and primary protector of your children, you have an obligation to know what your children are up to. You never know whether you need to be protecting your child from someone else or from themselves. It may feel deeply wrong to snoop around your child's room. But, if you suspect they are hiding something — and they are unlikely to fess up on their own — taking a look around their bedroom might be the only way to shed light on the situation.  If you decide to search, look in drawers beneath or between clothes, under the bed, in between notebooks, CD or DVD cases, in backpacks or duffel bags, in pockets of clothes hanging in the closet, inside books with pages cut out, inside the trash can, and under loose floorboards among other places.  Your child's room is a sacred domain to them, and having privacy there helps them learn to set boundaries with others. That's why snooping around in your child's bedroom should be done as a last resort — when signs have pointed to there being something amiss, or when you have clearly found evidence. As a part of your search, you might want to do a cursory glance at any electronic devices your child uses. Look through your child's tablet, laptop, and/or cell phone.  Be on the lookout for any social media apps that you have not given your child permission to use in addition to messenger apps. Your child could be communicating with people who are posing as teenagers and are in fact child predators. Be very wary if your child has many password-protected apps. Furthermore, if your child is adamant about not handing over passwords, this might be an indication that they are hiding something in their phone or computer. You may have to install monitoring apps on these devices to keep a closer eye on your child's usage. Certain apps are now being designed to help conceal photos, videos, messages, and other apps that your child does not want you to see. These include Vaulty and Hide It Pro. Stay on top of new apps such as these and beware if you find them in your child's phone.   Similar to their bedroom, technology is often a private thing for your child; limit these searches to when something seems wrong and your child won't open up.

Summary:
Search their room. Check their computer and/or phone.