Jan. 31, 2016: Police and fire officials investigate a house fire that killed five people at a home in Novi, Mich.. (Brandy Baker/Detroit News via AP)

Novi, Michigan -
Federal officials charged a suburban Detroit restaurant owner and his wife Friday with harboring immigrants who were in the U.S. without legal permission after a fire at a house he owned killed five employees about two weeks earlier.

Roger Tam, 55, was arrested Thursday and appeared Friday in U.S. District Court in Detroit. His wife, Ada Lei, 48, also has been charged, but has not been arrested because she is hospitalized for an undisclosed reason.

Five Mexican nationals lived in the basement of the home owned by Tam in an upper middle-class neighborhood in Novi, northwest of Detroit, while working at Tam's restaurant, Kim's Garden. The Jan. 31 fire has been ruled accidental and possibly caused by smoking; a smoke detector in the basement had been disabled. The basement had stairs to the first floor but windows made of glass block, which would prevent any escape in an emergency.

"He's a really good man," defense attorney Samuel Bennett told reporters after Tam's hearing. "He truly loved those men and boys as his own family."

The Associated Press was unable to determine the name of Lei's attorney to reach out for comment.

The treatment of immigrants who work in restaurants and live together has attracted widespread attention, most recently in the Chicago area, where Illinois' attorney general filed a lawsuit in November to stop alleged civil rights violations in housing and pay. And in Michigan, there are two cases involving farm workers pending in Tuscola and Huron counties, U.S. Attorney Barbara McQuade said.