KENT, Wash. - With the Fourth of July around the corner, police are reminding dog owners to look out for tennis ball bombs.

These devices are often hidden or disguised, and can pose a threat to dogs and humans. The tennis ball is implanted with a small explosive that serves as a homemade firecracker.

A tennis ball bomb has turned up before. In February, a local geocacher found the homemade device at Everett's Silver Lake Park. Luckily, no one was hurt.

Ray Friis was treasure hunting at Everett's Silver Lake when he made a bombshell of a discovery.

The Kent Police Department recently held a community meeting when a resident asked how to identify a tennis bomb. Police responded, "A tennis ball bomb is very easy to identify. It is a real tennis ball that has some sort of fuse sticking out of it. Here is a picture of one. The tennis ball could also be completely wrapped in duct tape with a fuse sticking out."

If you think you have come across such a device, proceed with caution and contact your local authorities immediately.