Can we ask existing tenants to sign a new rental agreement?

[Megan Barrett]

My Mother owns a single-unit home in East LA, in a desirable neighborhood, that she inherited 8 years ago. It's been a rental property since her father owned it, and the current tenants are a family that has occupied it for over 23 years.

There have been quite a few mistakes my mom has made along the way since taking over with these tenants, but a big one was not locating the original rental agreement they signed, and not having them sign a new agreement once she took ownership of the property. My mother lives 50 miles away, so she hasn't made frequent visits and has given these people the benefit of the doubt, believing its hard to find nice, honest tenants and since the husband works in maintenance and claims to do upkeep around the property. I'm starting to help deal with the management side since its an overwhelming task for my mom, and one of the first things we're planning on is a visit to the house. We gave 48 hour notice and will check it out this weekend.

We aren't under the RSO rent control, so we'd like to raise the rent significantly since they have gotten a steal for much too long. So on this visit we're planning on handing them a 60 day notice of the increase, since it's above 10% of their current rent. But we'd also like to have them sign a new rental agreement, with this increase noted, and have them list their additional occupants so we can charge the 10% per person/month also. The reason for noting the extra tenants is that their children are now grown, but 3 of them are still living in this 2 bed/1 bath, 1050 sq ft home, with the garage illegally converted to an extra bedroom (allowed by my grandpa originally).

So, can we ask them to sign this new Rental Agreement and is there any way to request a security deposit at this point in their Tenancy?

We are planning on asking them to move out soon (so we can spruce it up for me to move in), so it does feel like quite a bit of effort to ask for a SD, but we want an official agreement in writing before. We also aren't sure how they'll respond to an eventual notice to evict, so this is an attempt to have things documented.

By happenstance I have a mutual friend with the neighbor directly across the street from the property, and he's been able to give me insight of their less-than neighborly habits. Such as: leaving dead cars in the driveway for years, and parking others in front of neighbors' houses, and having parties with 60+ people. He also confirmed that they had a film crew on the property last summer for multiple days. I was able to pull the public records to confirm this happened. I even contacted the Production company and confirmed they knew the tenants and that they'd signed as the owners, consenting to the filming. We're positive they pocketed at least $8k from the filming.

This has me in an uproar, but I truly believe now it could cause more problems than its worth to bring it up or seek legal retribution for the fraud they've committed and know there are other options.

Anyway, I'd be grateful to hear whatever expert or experienced advice is available through this forum!