Barriers designed to absorb oil are placed near a damaged transformer hit by gunfire in Carthage, North Carolina.

A version of this story appears in CNN’s What Matters newsletter. To get it in your inbox, sign up for free here.

CNN  — 

The motivation behind an attack on the electrical grid in a North Carolina county remains a mystery.

But the method – apparently coordinated attacks on multiple substations – exploits a vulnerability that has long been a source of concern for authorities warning about domestic terrorism.

Just last week the Department of Homeland Security renewed a national bulletin to warn of attacks on critical infrastructure.

A removed gate at a substation; gunfire disables transformers

The details of this particular story are only starting to come into view, although Moore County, North Carolina, remains plunged in darkness. The FBI has joined the hunt for answers into how attacks on substations left around 40,000 without power over the weekend.

In a Sunday news conference, the county sheriff described the attacks as “intentional” and “targeted,” but had no reason why the person or persons involved would choose the place.

What authorities are saying

CNN’s Whitney Wild, reporting from Moore County, mentioned online rumors that disrupting a drag show planned for Saturday night may have been the cause of the attack, but authorities have not confirmed that and said no person or group has claimed responsibility.

What authorities have confirmed is that someone or some people removed a gate at one substation from its hinges. The damage to transformers was apparently caused by gunfire, although it’s not clear what kind of weapon was used.

Most of the roughly 40,000 people who lost power aren’t expected to get it back until Thursday, according to Duke Energy.

Life without power is causing problems

Mike Cameron is the assistant town manager and fire chief of Southern Pines, North Carolina, which is in Moore County.

Appearing on CNN on Monday, he said medical calls have increased as people who rely on oxygen and plug-in medical devices struggle.

In temperatures that have dipped almost to freezing overnight, people have gotten creative to heat their homes, which has led to an increase in calls about house fires.

There has also been an increase in emergency calls about traffic accidents, “just because our traffic lights are obviously not working,” he said.

A ‘terrorist’ act

Southern Pines Mayor Carol Haney did not hold back on her message to whoever is responsible for plunging her town into darkness.

“It is just a horrible, horrible terrorist, in my opinion, act. Cowardly,” she told CNN’s Victor Blackwell on Monday.

The mayor of Pinehurst, North Carolina, John Strickland, said on CNN that investigators will have to determine if this was a targeted attack by domestic extremists, but he said it was meant to be destructive.

“This is clearly an act that was intentional, very forceful and an act of vandalism to create a situation where the citizens of Pinehurst and Moore County are lacking heat and other support services at the present time,” he said on “CNN Newsroom.”

FirstHealth Moore Regional Hospital is currently being powered by diesel fuel, according to its president, Jonathan Davis, but elective procedures have been delayed.

The power grid is an ‘attractive target’

CNN’s chief law enforcement and intelligence analyst John Miller said this type of attack has long been feared.

The American electrical grid is decentralized and controlled by a hybrid of public and private entities.

“The challenge is most of these places are outdoors, most are in remote areas and most of them are available for attack from a long distance,” Miller said on “CNN This Morning.”

He also noted there has been an uptick in chatter among various anti-government and ecoterrorist groups who consider attacks on the electrical infrastructure as a way to create chaos in the US.

The aim may be chaos

In particular, Miller said right wing neo-Nazi groups have suggested creating a chain reaction of attacks to systematically take down the power grid.

“Their theory is that if you identify the key nodes and you knock out one and they divert power to the next one, and you knock out the next one and the next one, a domino effect can actually start to topple the national grid and plunge the nation into darkness and chaos,” Miller said.

It’s obviously not clear if this North Carolina attack is anything along those lines, but the Department of Homeland Security has been warning about such attacks for some time.

Attacks on power substations are not unprecedented

Sniper fire hit a Silicon Valley substation in April 2013, when 150 rounds from an assault rifle took out 17 transformers. Workers rerouted power in that case, but repairs to the transformers took nearly a month.

Miller said that after that incident, power companies and the government undertook a systemic review of grid security and made changes to add more cameras and motion sensors.

In January 2022, CNN’s Geneva Sands reported on a DHS memo about potential electrical grid threats from extremist groups angry at the outcome of the 2020 presidential election.

Violent extremist groups have identified the electrical grid as a “particularly attractive target,” according to the intelligence bulletin, and have drawn up specific plans.

In October 2020, the memo noted, White supremacists in Idaho were charged with conspiracy for trying to damage transformers in that area.

Also, in May 2020 the government charged followers of the Boogaloo movement, which believes there is a civil war coming, for allegedly conspiring to attack a substation in Las Vegas. Their larger goal was to incite riots and violence.

Unsophisticated small-scale attacks are unlikely to cause the kind of large-scale meltdown that anti-government plotters envision, but they are likely to cause substantial harm and expensive damage – which is precisely what’s happening in Moore County.

Possible scenarios

Juliette Kayyem, a CNN analyst and the former assistant secretary for intergovernmental affairs at DHS, said on CNN’s “The Lead” that investigators are probably looking at three possible scenarios:

Foreign attack. She said this seems unlikely, since Moore County is a rural area and not the expected target for a foreign actor.

Hate crime or domestic terrorism. She noted the lights went out at the drag show, which was organized by a LGBTQ group, just as it began.

Insider threat. Kayyem noted the knowledge it would take to disable the substations could be a clue.

“You don’t just drive by these places and know where to shoot,” she said. “(Investigators) will be looking at the potential there was either casing or someone who knew the area, the facilities and knew where to shoot. These aren’t drive-by incidents,” she said.