Dog owners in the Amman Valley are being warned to keep a close eye on their pets following a spate of thefts.
There is a £200 reward for Gypsy, missing since 1 February
About 10 Jack Russells have gone missing from the Glanamman and Garnant areas in recent months and police believe dognappers are responsible.
One, a four-year-old called Gypsy disappeared two weeks ago and her owner Julie Edmonds has been left devastated.
"I've got three other dogs and I'm terrified to even let them out in the garden," she said.
Ms Edmonds said Gypsy, an all-white Jack Russell, went missing on 1 February after wandering out of her garden in Garnant.
"I'm just worried sick and I'm not sleeping at night," she said.
"I've been phoning the dog wardens and police every day but there has been no sign.
"I've put posters up in the local shops, garages and post office and have given them to every dog walker I see.
"There is a £200 reward but I would willingly pay anything to have her back."
Ms Edmonds said she feared for the safety of her other three dogs - two Jack Russells and a sheepdog.
"We are having 6ft (1.8m) gates put up at the side of the house and we having security lighting.
"I'm having all the dogs micro-chipped this afternoon.
"I'm so vigilant when they are out now and I'm with them all the time."
Police community safety officer for the area Rob Chapman said: "For any dog owner to lose their pet can be a very traumatic time, but for 10 to go missing from the same area and in such a short time is very worrying."
He has urged anyone who sees anything suspicious to contact police.
Phone Dyfed-Powys Police on 0845 3330200 or Crimestoppers on 0800 555111.