The 24-year-old is charged with three felony counts of animal cruelty and one charge of attempted animal cruelty.
VIDEO: Owners present at hearing for accused San Jose cat killer
On Friday, prosecutors released photos of two collars, hoping the owners of the cats will come forward.
SJPD asking public to help ID 2 cat collars found in cat killer suspect's car when he was arrested earlier this year pic.twitter.com/ucwOPvAeuZ— Vic Lee (@vicleeabc7) December 11, 2015
They're also trying to track down the owner of a female orange, long-haired tabby suspected to have been killed by Farmer in October.
VIDEO: Man accused of kidnapping, killing cats in San Jose