Moni and Jim Thompson, with their surviving dog, Posie, have had four dogs killed and left on the railway tracks near their home. ((CBC))

Two dogs belonging to an Alberta couple have been killed and left on railway tracks near their home, little more than a year after two of their dogs were shot to death.

"It's so surreal," Moni Thompson said. "It's so hard to wrap your mind around it, that this would happen again, and that we just have to revisit this again."

Moni and her husband Jim live outside Sherwood Park, east of Edmonton, where neighbours found the bodies of basset hound Ellie Mae and German shepherd Schultz on Wednesday, about 300 metres away from where two of their dogs were found dead in May 2009.

Their basset hound Annie and Belgian shepherd Rio were shot last year; police believe someone poisoned Ellie May and Schultz this week.

"We don't believe that it's random, and at this point, we're looking at every avenue to link the two incidents together," said Strathcona RCMP Const. Wally Henry. "We believe that they're connected."

Police said they think someone in the community is likely responsible and they will interview neighbours as part of the investigation. They urge anyone with information to contact police or Crime Stoppers.

Thompson said she was alerted to a problem on Wednesday by her surviving dog, Posie, another basset hound.

The other dogs, which the couple got after the first two were killed, had left the yard, so Thompson started to call them.

"I started calling and calling and whistling and whistling and nothing. All day I was calling," she said. "I'm thinking, 'This can't be happening again.'"

Thompson is very close to her dogs; Rio helped her through a three-year battle with stomach and breast cancer.

She finds it scary that it's happened again.

"When does it stop? Where does it stop?" she asked. "You know, when does it get to kids or humans … somebody's gotta stop this person, 'cause it's just a scary, scary thing to think of what could happen next."