Authorities say they believe two high-voltage transmission towers that knocked out power to 17,000 customers surrounding Oak Creek, Wis., were knocked over as the result of an intentional act.
It definitely looks like they are tampered with,'' Oak Creek Police Chief Thomas Bauer said Sunday.
The investigation, which includes the Joint Terrorism Task Force and the FBI, was continuing Monday.
Bauer said bolts were removed from a plate that connects the legs at the base of the 80-foot towers, he said.
"It does look like it's for the purpose of weakening the structure so it would fall,'' the chief said. He refused to specify how many bolts were removed or how they were removed.
FBI Special Agent Jeffrey Troy said his agency has issued a general warning to other municipalities to be on the lookout for tampering with infrastructure. He said FBI offices nationwide were alerted.
One transmission tower fell on another one Saturday, which took out some We Energies distribution lines, officials said. The towers were owned by American Transmission Company.
ATC spokeswoman Maripat Blankenheim said the towers were last inspected by air in the spring and were fine then. She said authorities on Monday would discuss the possibility of a statewide inspection of towers.
Downed wires lay across railroad tracks throughout much of the day Sunday, putting passenger and freight trains from Amtrak and Canadian Pacific Railroad on hold for 26 hours, Bauer said. The trains resumed at 7 p.m. Sunday, after authorities cut the wires, he said.
All 10 trains traveling between Milwaukee and Chicago were canceled Sunday, said Marcie Golgoski, the company's spokeswoman.
About 17,000 We Energies customers, including the General Mitchell International Airport, were without power for about four hours Saturday night.
The outage shut down screening equipment at the airport and flights were delayed as passengers and luggage were hand screened, said Pat Rowe, airport spokeswoman.
In February, a 62-year-old Spokane, Wash., man was sentenced to 27 months in federal prison for removing bolts in legs of about 20 electrical transmission towers in California, Oregon, Washington and Idaho.
Michael Devlyn Poulin said he tampered with the towers to show how vulnerable America is to terrorist attack.
Troy said other towers have also been targeted in the past.