My question involves landlord-tenant law in the State of: California
A year ago I moved into a three bedroom apartment with two other friends in the middle of a lease becuase another friend moved out. After I assumed the lease, a friend of the other tenant took up occupancy on the couch temporarily. I wasn't asked if he could move in but I kept to myself since he was a friend of the tenant. Needless to say the temporary arangement became long term that the other tenant demanded to be compensated for his illegal occupancy because his belongings were there. All tenants of the lease were compensated equally for his arangement because it was the friend of the other tenant and it was agreed that he would only be present on the weekends and another lease term was signed.
After a few months of the signing of a new lease term, the tenants had a falling out with me. Considering I was in the middle of another lease I was stuck and kept my belongings there but never slept at that apartment. During that time, the same friend of the other tenant took up occupancy again without my permission but this time was given a key to the apartment and had his belongings at the apartment without being on the lease. I haven't been on good terms with the roomates that I gave notice that I was moving out and yet that same friend that illegally took occupancy without signing a lease still has a key and his belongings at the apartment without any sort of compensation to me. Do I have any legal grounds to terminate the lease since the other roomate technically sublet the apartment unofficially to his friend the first time and the complex does not allow subleases. I don't know if the apartment complex will do anything except to have the illegal tenant evicted. I've tried to pay for the other roomates to move into two bedroom and find a replacement to no avail. Is there anything I can do to break this lease?

