05/27/2012 04:46 EDT | Updated 07/27/2012 05:12 EDT

Neighbour may have helped find missing kids in Mexico

Two Winnipeg children who had been missing for nearly four years were found in Mexico after a man raised concerns about his neighbour, according to a private investigator.

Dominic and Abby Maryk had been missing since August 2008, when they went on a two-week vacation as part of a court-approved visit with their biological father, Kevin Maryk.

The children, who were seven and five years old at the time, were not returned to their mother, Emily Cablek, as planned. Cablek has legal custody of the children.

Winnipeg police have said they believe Maryk abducted the children and removed them from Canada.

The Maryk children were found Friday in Guadalajara, Mexico, according to Wilhem von Mayer, an investigator based in the United States, and a Mexican missing persons organization known as the FIND Foundation.

Contacted by neighbour

Von Mayer told CBC News he got involved in the case when he was contacted by a man in Mexico who was concerned about a neighbour's suspicious behaviour involving two children.

According to von Mayer, the neighbour alleged that the children were kept "locked in" until late at night, when a man would take them outside.

"At eight o'clock at night he would take them out and not return the kids until, like, two or three o'clock in the morning," von Mayer said in an interview.

"That's what raised suspicion for this guy, and that's the reason that he started to try to find out what the real story was."

Von Mayer said the concerned neighbour went to him after he had tried to contact Mexican authorities but nothing was done.

With the help of a local television station, the children were found on Friday afternoon, von Mayer said.

"All because of one brave individual, his neighbour, he's the one that made it happen," he said.

Details coming on Monday

Police and the Maryk children's family members in Winnipeg have been tight-lipped about the latest development so far this weekend.

Police have only said they have been involved in an investigation with Mexican authorities and that "significant developments" took place on Friday. They said more details would be released on Monday.

Over the last four years, police had issued pleas for the public's help in locating the missing children. In December, police posted a YouTube video featuring photographs of the children and interviews with Cablek and investigators.

"I want my kids to know how much I love them; that I'll never, ever stop looking for them," Cablek said in the video. "They're my life and life hasn't been the same since they've been gone."

Earlier last year, police released age-progression photographs that show what the children may look like today.

Police had issued Canada-wide warrants for Kevin Maryk and two other men police believe may have helped in the abduction: Cody McKay, who is Maryk's nephew, and Robert Groen, who police describe as an associate.

The following is a video posted by the Winnipeg Police Service in December, when they pleaded to the public for information on the whereabouts of Abby and Dominic Maryk.