I am a wedding videographer, but the camera was lost at my host’s house on the day of the wedding.

Look for whoever stole it. They are your customers and have no obligation to take care of your things. Why would you sue them?

If you report a crime, you can ask others to assist in the investigation. (It’s just a request)

Only the public security organs have the power to “request” citizens to assist in investigations. Why should a common man demand anything from others? If you want someone to check for you, be kind and sincere to them. It's not impossible at all. Communicate patiently in everything, and if you have something to say, things will fall into place.

Do you think so?