One tri-state police department is warning residents about bicycle thefts. 

The Nassau County Police Department put out a list of tips to prevent bicycle thefts.

Follow the tips below to help safeguard yours:

1. Lock your bike when unattended;

2. U-lock the frame and one wheel; 

3. Use a bike rack - sign poles are not as secure;

4. Lock your bike in well-lit and well-traveled areas;

5. When not in use - overnight for example - consider storing the bike inside a secure location, instead of outside;

6. Take easily removed items with you (like lights, quick-release seat posts);

7. Report stolen bicycles to the police;

8. Write down your serial number. It's also very helpful to have a picture of your bicycle and original sales receipt, if possible. If your bike gets stolen this will help police find it, and will help prove ownership.