The mother of four young boys who were allegedly beheaded by their Somali-Canadian father says she doesn't know of any motive for the killings.

Police in Somalia arrested Omar Hassan, 60, after the children, aged 11, nine, seven and six, were killed Monday, Qadro Addawe told The Canadian Press.

The alleged slayings happened in the central town of Beledweyne, about 330 kilometres north of the capital Mogadishu.

The Somali town of Beledweyne, about 330 kilometres north of the capital Mogadishu, is in shock following the beheading of four young boys allegedly by their Somali-Canadian father. (Google Maps)

Speaking from Mogadishu, Addawe said Hassan had been a taxi driver in Calgary and had returned to Somalia 10 months ago.

CBC News contacted Calgary cab companies as well as the Taxi Commission, and there was no record of Hassan.

Calgary cab driver Mohamoud Fidow, who has known Hassan for more than 20 years, said his friend actually lived and worked as a taxi driver in Fort McMurray, Alta., and in Yellowknife. Government of Yellowknife officials confirmed to CBC News that Hassan first took out a taxi permit to drive a cab in the city in 2006.

Fidow said he lost touch with Hassan after their last visit in 2009.

"And that time he was not OK," said Fidow, adding Hassan told him he was under a lot of stress and suffered from depression and lack of sleep.

He said he is still trying to come to terms with reports that his friend is accused of murdering his children.

Children had Canadian citizenship

Addawe said the children had never been to Canada, but had Canadian citizenship through her estranged husband, who had migrated to Canada 30 years ago.

"They were born in Kenya, but they were Canadian because the father was Canadian," she said.

A regional police commissioner told Agence France-Presse Wednesday that the children's bodies were found near a village and have been buried.

The news service quoted Col. Isak Ali Abdulle as saying: "The man handed himself in and is in custody now. I think he is not mentally fit but we are questioning him."

Addawe, 29, said she does not know of any motive for the killings.

She insisted Hassan was mentally stable.

"He had some health problems, but he had no mental problems."

Addawe said her own efforts to migrate to Canada had been unsuccessful.

A spokesman for the Department of Foreign Affairs in Ottawa said they were aware of reports of "a possible consular case in Somalia," but said consular officials have not received a request for assistance.

The accusations have also shocked members of the close-knit Canadian Somali community who are watching anxiously as details emerge.

"The community is very sad about it. It's unheard of," said Mohamed Jama, president of the Somali Canadian Society in Calgary.