A TORN parent begged God's forgiveness and wished comfort on the owners whose beloved pet they decided to keep in an anonymous letter to a devastated Warwick family.

Agony over the decision not to return four-year-old cat Princess to the family that raised her has brought pain and disbelief to Warwick mother Jane Didden.

Ms Didden said she was completely shocked when an anonymous letter appeared seven weeks after her precious 'Princess' went missing.

But discovering the cherished animal was alive, close by and had been re-named by a different family was almost worse than believing the cat might have been killed, Ms Didden said.

"I know it's a sin and I am so very sorry to tell you that we are going to keep Prancer, but I thought you might have some closure knowing she is alive and well," the note reads.

"It's your cat and I have agonised all week over contacting you to return her but so much time has passed and my daughter will be devastated if she lost her so I just can't do that to her."

The note explains that Princess, whom the neighbouring family re-named 'Prancer', got caught in a humane trap set to protect their chickens.

Initially the anonymous parent put up signs in Bunnings and IGA but received no reply.

"My daughter nursed her back to health and they have become inseparable," the letter reads.

"Prancer sleeps with her every night and snuggles up with her in the morning.

"This week a neighbour mentioned a family around the corner ... had lost a cat ... so we did a search (on social media) and found your post and photo.

"It's your cat."

Ms Didden said losing Princess had affected her household deeply.

"The whole house isn't the same without her. Even though everyone is tyring to be brave there is just that underlying current of sadness," she said.

Ms Didden described Princess as a "big personality" who constantly expressed affection.

"My 93-year-old father in law was besotted by her. He asks every day about whether she is coming back," Ms Didden said.

Meanwhile, Warwick locals have rallied behind Ms Didden's public appeal to get her cat back.

"Can't believe anyone would do this knowing that she has a loving home," wildlife carer Pascale Farrow said.

Mother-of-two Fawn Dunkley said the news was "so upsetting".

"I really hope you get your Princess back. Please if the person who did this is reading... give her back."

Ms Didden, who is new to Warwick, said she didn't want to come across as "aggressive" or "forceful".

"I don't want to point fingers or have them charged, I just want the cat back."

Anyone with information can contact Jane on 0403237840.