DENVER — Mutilated cats are turning up in Denver and its suburbs with sickening frequency: Four more bodies were found over the weekend, bringing the total to at least 41 in the past year.

Christy Hughes had stopped reading stories about the attacks. Then her husband, Kim, found the eviscerated body of their 15-year-old cat, Bugsy, outside the front door of their Aurora home two weeks ago.

"I blame myself, because had I read it, I never would have let my cat outside," she said Monday. "I've had a hard time forgiving myself for that."

Victims like Hughes, police and animal control officers are worried that despite dozens of gruesome attacks in the Salt Lake and Denver areas, pet owners still are letting their cats roam outside.

"I've had people say, 'They don't like to stay inside,' " said Temma Martin, spokeswoman for Salt Lake County Animal Services. "Well, look at the stakes here."

One of officers' concerns is that those who practice animal abuse may go on to attack people. In several of the year's past cases, it appears the attacker kills the cat, then taunts the owner by bringing back the remains.

Authorities say at least 40 mutilated cats have been found in the Denver area in the past year, and some may have been killed by another animal. Martin said the toll in Salt Lake City is 10 cats and another unidentified animal.

Authorities in the two cities are comparing notes on the attacks, and it is unclear whether there is any connection. But the idea that a suspect may take glee in publicity has authorities limiting details on their investigation.

"We don't want to make someone happy that they're seeing themselves on TV or hearing it on the radio," said Kathleen Walsh, police spokeswoman in Aurora, where at least 17 bodies have been found.

Others say education may help prevent attacks or find a suspect.

"My plea to everyone is to keep your cat inside," Hughes said.

The attacks in Utah and Colorado have come mostly during the spring and summer and apparently happen late at night. Some of the animals were cut with surgical precision.

The Colorado penalty for aggravated cruelty to animals is up to 18 months in jail and a $100,000 fine.

Hughes said Bugsy, the multicolored cat she got from the Denver Dumb Friends League 12 years ago, was attacked sometime between 1 a.m., when he last went out, and 6:15 a.m., when he was found dead.

"For a week I couldn't sleep because I just kept seeing my cat over and over," she said. "It breaks my heart seeing somebody else go through this."