Two Winnipeg siblings who have been reunited with their mother four years after they were abducted need privacy now so they can recover, child experts say.

Authorities found Abby Maryk, 9, and her brother Dominic Maryk, 11, inside a fortified residence in Guadalajara, Mexico, on Friday.

The two children had been missing since August 2008, when they went on a two-week court-approved vacation with their biological father, Kevin Maryk, but never returned.

Over the weekend, Abby and Dominic were reunited with their mother, Emily Cablek, who has legal custody of the children.

Christy Dzikowicz of the Canadian Centre for Child Protection, who travelled with Cablek and others to Mexico, said the reunion was not as joyous as some may expect.

"The initial moments, for sure, were just sort of explaining where we were going and what we were doing, and not putting a lot of pressure on the relationships or the reunion," Dzikowicz told CBC News.

"So there were very quick hellos, but the kids were scared."

Privacy needed

Kevin Maryk and a friend, Robert Groen, have been arrested and detained in Mexico City.

Kevin Maryk, left, and Robert Groen, right, have been arrested. Police are still looking for Cody McKay, centre. (Winnipeg Police Service)

Police in Winnipeg say they are in the process of extraditing the men to Canada for prosecution.

A Canada-wide arrest warrant remains in effect for Cody McKay, Maryk's nephew. Police believe he was also involved in the children's abduction.

Dzikowicz said Dominic and Abby Maryk are getting medical and psychological help, but what they need right now is privacy so they can feel safe in their new surroundings.

"They need to be in an environment where they have supports around them," she said.

"Even I notice when there's extra people in the room, that causes anxiety, never mind people who are trying to take photos."

Like 'robots' in Mexico

Winnipeg police said the Maryk children had been moved at least five times over the past four years to different locations in Mexico.

What Dominic Maryk, top, and his sister, Abby, looked like before they went missing on Aug. 30, 2008. (Winnipeg Police Service)

Dzikowicz said the children lived in poor conditions in Mexico, as they had no schooling, no friends and no medical assistance during the time they were hidden by their father.

They were never taken out during the light of day and only breathed fresh air when they were allowed out at night, she added.

Juan Manuel Estrada of FIND, a Mexican missing persons foundation that helped authorities track down the Maryk children, told CBC News the kids were kept in a three-bedroom condominium, surrounded by four guard dogs and numerous security cameras.

People in the area told Estrada the Maryk children were rarely seen outside during the day, except on one occasion when someone claimed to have seen them locked inside a car — with the windows rolled up — for an hour on a hot, sunny day as Kevin Maryk spoke with a neighbour on the street.

The children appeared to be like "robots" that did not move or do anything, Estrada told CBC News in Spanish.

Atzdi Camarena, a national television reporter in Mexico, said witnesses told her the Maryk children were not allowed to talk to anyone.

The few times the children tried to speak with neighbours, they were yelled at, Camarena said.

Lifetime of recovery ahead

Dzikowicz said she has already noticed an improvement in the Maryk children since they returned to Winnipeg.

But Liss Haviv of Take Root, a U.S.-based support group for abduction survivors, said recovering from the experience can be very traumatic for young people.

"The child … is surrounded by society and messages that it's over and you must be so happy now," she said.

"So they put on a brave face and they smile for the cameras, but inside their entire world is crumbling."

Haviv, who was abducted by her mother when she was a child, said the Maryk children have a lifetime of recovery ahead of them.

"The enormity of the worldview that's being shattered at this moment of recovery, while the world around them is celebrating, can't be overstated," she said.

Most children who have been abducted can be very adult-like and immature at the same time, Haviv said.