A cat killer is snatching pets from suburban streets, butchering them and dumping their mutilated bodies on their owners' doorsteps.
At least ten have been killed since May in Chichester, Burgess Hill and Haywards Heath.
A reward of £2,000 is on offer for information leading to the conviction of the killer.
Witnesses say a man has been seen trawling estates with a net at night.
Some have heard the cats howling as they are grabbed.
It is believed the man captures the animals, bundles them into a vehicle and takes them away to behead and butcher them before returning them to their owners.
In the most recent incident in Burgess Hill, the cat's corpse was returned with its head pushed back inside its body.
Four cats on one Chichester housing estate and three in Haywards Heath have suffered a similar fate.
Heads have been left in flowerpots and carrier bags.
Some cats have returned alive with eyes, legs, tails or patches of fur missing. At least 30 more have disappeared.
Margaret Knight, of Henry Close, Chichester, has lost both her cats and says she will never own another pet.
A collar returned by police is all Mrs Knight has left of her treasured pedigree Jenny, ten, whose head was found in a flowerpot near her house five days after she disappeared on July 19.
Mrs Knight said: "Jenny was like a child to me and her last moments would have been absolute terror. I am devastated."
She is certain her other cat, Cindy, who disappeared on May 31, has also been slaughtered.
She said: "I had had Cindy 16 years and she always came home for her supper at 10pm. She never missed a meal.
"One day she just didn't come back. We couldn't find a trace of her. I am in no doubt she went the same way as Jenny."
Brenda Stubbington, who lives on the same estate, found her cat Charlie dead in an alley near her home.
The animal was mauled but not mutilated, perhaps because the attacker was surprised.
She said: "I had been making sure my cats were indoors but one night I couldn't find Charlie anywhere.
"I went to bed and that night I heard the sound of a cat screeching at 5am. The next morning I found Charlie dead.
"My neighbour heard the noise too and ran out and scared off whoever was there.
"They didn't have time to finish the job properly."
June Bailey, who runs a pet detective agency in Worthing, said: "I'm sure the incidents are linked.
"It is obviously someone who has a severe psychiatric problem."
West Sussex Wildlife Protection has put up a £1,000 reward to help find the killer.
Shopkeepers and pet owners in Haywards Heath have pledged another £1,000.
The RSPCA is investigating the killing of a cat in Haywards Heath on July 4.
Anyone with any information should contact the charity on 08705 555999 and Mrs Bailey on 01903 772176.
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