Detroit -- Members of a radical environmental group that opposes urban sprawl have claimed responsibility for fires at four luxury homes being built in Detroit's outer suburbs.
The claim by the Earth Liberation Front members was posted on the group's Web site.
FBI agent Willie Hulon said Wednesday he also believes the group was behind the blazes.
Fires destroyed two homes in Washtenaw County on March 21 and two nearly completed homes in Macomb County on June 4.
The letters "ELF" and anti-sprawl messages were spray-painted on houses or construction equipment at both scenes.
Authorities are treating the fires as criminal acts, not terrorist activity, Hulon said.
Responding to an e-mail request for comment, the environmental group said it doesn't oppose development that fills community needs.
But, it said, luxury projects "are accelerating the destruction of forested areas, wetlands and other areas of environmental concern across North America."
The group has claimed responsibility for a number of other illegal acts, including the destruction of a genetic engineering research project at Michigan State University in 1999.
A construction industry representative condemned the fires.
"The construction that takes place in these communities is based on people's demand and their right to exercise freedom of choice," said Steve Perlman of the Building Industry Association of Southeast Michigan.