Thank you for your immediate help.

I have been traveling for several months during which time my friend sublet my apartment on my behalf. He did not receive or give anything in writing but made a verbal agreement and accepted cash for the first month.

I have now returned to find that the subletter has bounced two checks and given a skilled runaround avoiding my calls and not even coming home.

He is now one month and a half late on rent (has been missing for 4 days) with 15 days left of what was to be the extent of the lease.

Can I confiscate his property to make up for my losses... can I lock him out?
How do I evict him?
Do I have to follow a legal process or can I just ask him to leave?
What rights do I have in California?

No you can not lock them out and you can not just take their belongings. You will have to after you give them notice file for an eviction in family court. You can ask them to leave but they can laugh at you also.