Federal authorities, who have been baffled by more than a dozen attacks on San Francisco Bay Area data lines, are probing whether there is any connection between that vandalism and the Super Bowl. The NFL's big game will be played February 7 at Levi's Stadium in Santa Clara, just south of San Francisco.

An Internal memo between the FBI, Department of Homeland Security, and others says the agencies have no "credible threats to or associated with Super Bowl 50 or related events." But the memo, obtained by NBC's News 4 in Washington, DC, says the spate of fiber optic cable severings across the San Francisco Bay Area raises "the concern individuals may be using these incidents to test and prod network durability in conjunction with a more complex plot."

The FBI declined to respond to Ars' inquiry. A former FBI agent familiar with the memo, however, stressed that the authorities have not found any credible threats and that the agencies were considering every possible nefarious scenario they could think of before the big game.

Jeffrey Harp, who retired from the FBI San Francisco bureau in October as assistant special agent in charge, said the routine threat assessment was sent to several law enforcement agencies, including local police departments that will be involved in Super Bowl security. "Those assessments cover everything from A to Z," Harp said in telephone interview.

"The FBI doesn't take anything for granted and assume everybody knows what the targets are," he added. "So they put these bulletins together as a reminder that there are terrorists out there targeting infrastructure."

What's more, the memo also asserted that drones used by "malicious" actors "may present a low-altitude hazard to aviation assets supporting the event, allow unauthorized video coverage of events, or pose a risk of injury to event-goers if an operator loses control."

There have been at least 16 severed cable lines in California dating to July 2014. The vandalism has disrupted iInternet, television, and telephone service for tens of thousands of customers on a host of networks and across a broad swatch of the Bay Area.

The authorities suspect that the vandals, who operate at night, may be posing as telecom maintenance workers.

The affected lines are about as thick as a finger and are covered with flexible conduit. They often carry Internet, television, and phone calls. The cuts have been performed in areas where there are no security cameras.