The FBI said Wednesday that it is "too early" to determine whether gunfire at a substation in Randolph County, North Carolina, this week was connected to December’s attack on the nearby Moore County’s power grid that still hasn’t resulted in any arrests despite causing outages for tens of thousands. 

"The FBI is working with the Randolph County Sheriff's Office to investigate after gunfire damaged an EnergyUnited substation on January 17, 2023," a spokesperson for the FBI Charlotte Division said in a statement to Fox News Digital Wednesday. "At this time, it is too early in the investigation to determine whether this case is connected to the ongoing investigation in Moore County." 

On Tuesday morning, EnergyUnited officials responded to an alarm that notified personnel of an equipment issue at its Pleasant Hill Substation in Thomasville, N.C. 

Crews found the substation transformer was damaged by gunshots and alerted law enforcement. The Randolph County Sheriff’s Office responded to the scene and suspect the attack occurred around 3 a.m. The FBI’s Joint Terrorism Task Force responded to conduct a parallel investigation.

FBI RESPONDS TO GUNFIRE AT ANOTHER NORTH CAROLINA SUBSTATION MONTH AFTER MOORE COUNTY POWER GRID ATTACKS 

The incident came nearly two months after Dec. 3 gunfire at several substations operated by Duke Energy in Moore County, N.C., left some 45,000 customers without power for several days. Tuesday’s damage didn’t cause outages. 

Moore County substation repairs

A Dec. 5 view of electric grid repair work in progress as tens of thousands remained without power in Moore County after an attack at two substations.  (Peter Zay/Anadolu Agency via Getty Images)

In an interview with Fox News Digital on Thursday, former Department of Homeland Security Assistant Secretary Brian Harrell, who was appointed in 2018 by former President Donald Trump, speculated that investigators will find "either a link to domestic terrorism or it is a disgruntled former substation contractor" behind the attacks. 

"If they had somebody, they would have already arrested them," Harrell said.  

 "This has the governor's attention. This has local legislators, Lynn Good at Duke Energy -- It's got everyone's attention. And so if they had some leads, if they knew something, something would have already transpired, I believe," he added. "I think this is why, again, I revert back to either a very sophisticated threat actor who knows something about substations or, in fact, an insider." 

North Carolina substation attack

This photo shows the gate to the Duke Energy West End substation in Moore County, N.C. on Sunday, Dec. 4, 2022. ( John Nagy/The Pilot via AP)

Harrell suspects a "concerted insider attack," involving a person or group with "intimate, professional knowledge as to what to shoot at, what to destroy, what to disable and how to go undetected." 

"A big part of the DV, domestic violent extremists, playbook right now is to go after critical infrastructure sites and energy is squarely in the crosshairs," Harrell noted. 

"Right now, there's a lot of chatter on some of these Facebook private portals. You go into some of these dark web areas of the Internet and a lot of it is focused on destroying critical infrastructure, specifically energy and grid components. And so, this is very popular," Harrell told Fox News Digital. "I think for most I call it domestic terrorists or people who want to destroy infrastructure, you know, an easy way to get people's attention is to have them lose their power."

Crews work to repair a Duke Energy substation in Carthage, North Carolina, as tens of thousands remained without power in Moore County on Dec. 5. (Peter Zay/Anadolu Agency via Getty Images)

Harrell explained how all the substations attacked in North Carolina so far are relatively low voltage – not sites holding the most critical assets ensuring the reliability of the electric grid. They’ve happened at substations generally with fewer physical security protections like cameras or intrusion detection. Lower voltage substations are generally remote and unmanned with just a perimeter fence under lock and key and maybe a substation engineer or a security person who comes by on patrol now and again, he said. 

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"We can't protect all things like castles and fortresses," Harrell told Fox News Digital. "Through a risk-based approach, we have to understand what are the crown jewels, what are the things that we absolutely must protect? And we protect those in some of the smaller voltage distribution level, substations don't necessarily have those same level of protections. To suggest that the grid is vulnerable and we're just sitting ducks here, I think is disingenuous. I don't think that's accurate." 

With a lack of video, Harrell said a part of FBI investigations likely involve combing cell records to see if any phones pinged in the area of the substations around the time of the attacks.