After a mysterious Internet outage this week affected customers in the San Francisco Bay Area–even reaching as far as Seattle–the FBI revealed it is investigating the incident. The Bay Area’s physical Internet infrastructure has been attacked by highly skilled saboteurs on ten other occasions in the past year alone.
According to the San Francisco Chronicle, the outage took place on Tuesday and vandalized cables owned by Level 3 Communications and Zayo. The attack primarily disrupted service for Wave Broadband, a popular west coast Internet service provider.
“Three major fiber cables connecting the region have been physically severed in what appears to be a coordinated attack on multiple Internet carriers beginning at 4:20 a.m. Tuesday morning,” Wave noted in a statement.
The FBI disputes Wave’s claims of a “coordinated attack,” but said at least 10 similar, mysterious attacks on fiber optic cable have taken place since July 2014. According to the agency, the attacks required specific telecommunications knowledge, as well as obtaining access to underground utility bunkers and cutting through conduit sheathing.
“The individuals may appear to be normal telecommunications maintenance workers or possess tools consistent with that job role,” the FBI said in a statement, The Hill reports.
No one has claimed responsibility for the attacks, and the motive remains unknown at the time of writing.