A man in California, who confessed to stealing, torturing and killing 18 cats, has been jailed for 16 years.

A judge in Santa Clara Superior Court read the names of all the cats killed by Robert Farmer, 26. Experts said that one of the cats even showed signs of having been sexually abused.

Several blood stains were found in Farmer's car, as well as the remains of one of the cats, when he was arrested in October 2015.

Police subsequently determined that he had killed 18 animals in a gruesome two-month spree, with several pets found dead – two of them in rubbish bins.

Farmer pleaded guilty to killing the animals and injuring three more in the Cambrian Park area of San Jose in the fall of 2015.

Inside a Santa Clara County courtroom on Friday (14 July), the cats' owners shared their stories before a judge.

"He will still be young when he's released," one woman said. "It's a terrifying thought to think of what could happen if he makes another mistake in his life."

A video footage from a security camera showed a young man taking away a 17-year-old cat named GoGo, with residents pointing the police to Farmer, The Mercury News website said.

Owner Miriam Petrova was at the court on Friday. "We finally can say goodbye to every cat that was involved in this tragedy," Petrova told NBC News.

Farmer admitted 21 felony counts of animal cruelty. He said he killed 18 cats and wounded three – and admitted to charges of misdemeanour battery and being under the influence.

"It feels like another man committed these crimes, but I know it was me. It's so hard to grasp I did this. I stole a member of their family. The fact that I was out of my mind was no excuse," a letter by Farmer was read out by his lawyer.

Santa Clara County Deputy District Attorney Alexandra Ellis dismissed Farmer's letter as an attempt to win leniency.

"The judge agreed with my analysis. She sentenced him to 16 years. We can only hope it is long enough," Petrova said.

Farmer has also been banned from owning or caring for a pet for 10 years after his release, and been given a restriction order keeping him away from Cambrian Park.