Authorities on Tuesday were investigating fires set in four luxury homes under construction inside an upscale gated community and searching for possible ties to a series of similar fires in the Phoenix area.
Investigators were trying to establish whether the fires were set by an eco-terrorist bent on preventing development in the desert.
The initials "CSP" were spray-painted on at least one home. The same initials--said to stand for Coalition to Save the Preserves--were found sprayed on a sign in front of a Phoenix home under construction.
Those initials also were found in notes at some of the 11 arson fires that have destroyed Phoenix or Scottsdale luxury homes under construction near mountain preserves since 1998 and in letters to the news media.
Members of a task force investigating the Phoenix fires were among those looking into the Pima County blazes. The Phoenix Fire Department has connected four of its area's fires to the same arsonist or group of arsonists.
Rural/Metro Fire Department District Chief George Good said eco-terrorism such as that in the Phoenix area has not been ruled out.
In April, Phoenix authorities arrested a Phoenix man as an investigative lead in their arsons. Court documents said the 49-year-old man had scrawled the letters "CSP" on a sign in front of a home being built near the Phoenix Mountain Preserve.
But the criminal-damage case, accusing the man of tagging a construction sign, was dropped because prosecutors did not meet a deadline for filing charges after his arrest.