Lewis was released from L.A. County Jail on September 21. We're told he had several criminal cases filed against him at the time of his death.
We do not know the nature of the offenses, but law enforcement sources tell TMZ ... the "Sons of Anarchy" star was also recently in rehab.
What's more ... we're told a dead cat was found in the house where Lewis lived with the landlady -- and the home was ransacked. Police are investigating, but Lewis is also suspected of killing the cat.
As we reported ... law enforcement sources tell TMZ they believe Lewis was either on PCP or Meth at the time of the murder. The 2 people who fought Lewis before he fell to his death from a roof told cops the actor exhibited "superhuman strength."