TORONTO -- American forces searched for Somali militia leader Mohamed Farah Aideed throughout Mogadishu for four months without success. Until recently, his second wife would have been easier to find: She lives in Canada, with the couple's four children, where she is under investigation for possible welfare and immigration fraud.

Aideed's two grown children by his first wife also are in Canada and also are being investigated for possible immigration violations, government officials said.

Members of Aideed's family have been here since the late 1980s, when most arrived as refugees.

Canada's refugee laws are among the most liberal of the developed nations, and Toronto is said to contain more Somali immigrants -- an estimated 30,000 -- than any other city in the world.

Somalis here said Canada's generous welfare system also helped attract Somalis, who for reasons of language or education may have difficulty finding work.

Aideed's second wife, Khadiga Said Gurhan, 38, has lived here openly since her arrival in 1989, even giving a few newspaper and television interviews. But she and her children are in hiding now, having fled the hordes of reporters and photographers who showed up in front of her house in London, Ontario, after the welfare investigation was disclosed earlier this month.

Joe Fontana, a member of Canada's Parliament from London, has demanded that Gurhan be deported, saying she is "using London has a safe haven while her husband's troops butcher and massacre U.N. troops. . . . She's collecting social assistance while her husband probably has millions buried in a Swiss bank account."

Ontario Premier Bob Rae has said it was not proven that Gurhan had broken any law. She was declared a refugee when she arrived and now has the status of legal permanent resident.

The allegation is that Gurhan returned to Mogadishu for five months in 1991 while continuing to collect welfare payments, without informing her case officer.

Carolyn Hackland, immigration spokeswoman for Canada's Ministry of Public Security, said several agencies of the federal and Ontario provincial governments are conducting a joint inquiry into the allegations but have reached no conclusions.

In addition, she said, the ministry is investigating allegations that Aideed's grown son and daughter, who live in or near Toronto, claimed refugee status in Canada while holding permanent-resident status in the United States. Their mother, Aideed's first wife, lives in California and is reported to be an American citizen.

Gurhan, who has been married to Aideed since 1984, is not speaking to the media, and a Somali who knows her said she is upset by all the publicity and wants to keep a low profile. She has done nothing illegal, he said. Earlier, Gurhan was quoted in the Toronto Sun as saying that she was happy living in Canada. "I don't like to live on welfare. It's shameful. But my husband has no job. He's a rebel. . . . Where could he get money?"

Her husband, she told Canadian Press, had been called on television the Hitler of Africa, "while he actually is the Martin Luther King."

Aideed's older daughter, Khadra Farah, 30, lives in the Niagara region south of here and also is supported by welfare payments. She told local newspaper reporters that the allegations about Aideed's family were spread by Somali factions opposed to Aideed, and she has denied doing anything illegal. Aideed's son, Abdullahi Farah, who lives in Toronto, has not spoken to the media and could not be reached for comment.