Unknown Renters - Squaters

[R DeMeritt]

I recently purchased a flip house in CA at a trustee sale, and have no idea who the renters are, and only one (of six) people living in the house has identified who they are, and they only provided a first name. I do know they are not the previous owner.

The one person who partially identified herself has said she has a written lease agreement, as well as one other unknown person in the house, but wont provide a copy of the agreement.

They pay no rent to me, and I doubt they have paid rent in quite a while. Can I attempt to collect rent while I'm going through the eviction process with them?

I offered a cash for keys agreement, which she verbally agreed to, but then rescinded when it came time to sign the agreement because I wouldn't pay each of the six people the same amount I would pay her. She claims to be the financially responsible party, which is why the offer was made to her.

Can I enter the property with a 24 hour notice to change locks, and provide the tenant with new keys?

How can I find out who the people are that live their? Rifle through the mailbox? Take license numbers of vehicles? etc...

Can I file an action against each adult person individually?

I realize even with the 24 notice to enter she doesn't have to let me in, but at the same time I'm liable to make sure smoke detectors are working and all safety issues are addressed.

She's already told me that she knows the system and can stay for at least 4 1/2 months before I can get her out.