Thread by @DavidBegnaud

Updates on Puerto Rico Power Outage:
The Bureau of Alcohol, Tobacco, Firearms & Explosives has joined the investigation into the cause of the explosion/fire at the Monacillo substation. FBI San Juan is leading the investigation. Engineers from LUMA are also involved.

Investigators and engineers are reviewing the surveillance video and logs accounting for who had access to secure facility.

There is still nothing that point to criminal activity or sabotage, according to a source with direct knowledge of the investigation. (If that changes, I will update as soon as I receive new information).

As of 3pm eastern time on Friday, LUMA reports that 19,000 subscribers still don't have power. Of those, 13,000 "are directly served by the transformer damaged by the fire yesterday."

LUMA says: "installation continues of the mobile substation that was transported to Monacillo to replace the once affected yesterday by fire. Once that is compete LUMA will reconnect the 13,000 customers directly affected by the fire." Luma expects that to happen by 8pm.

A law enforcement official told me that investigators are looking into 3 scenarios as to the cause of what happened. Was it:
1. accidental
2. a result of faulty equipment
3. sabotage

The ATF has offered to have their national response team to respond to Puerto Rico. So far that team has not been requested. That team is usually sent if something suspicious is found. So far, a law enforcement source tells me that nothing suspicious has been found.

Another update: regarding Luma's claim that a cyber attack to their website lead to users not be able to access Luma's site or app - I've been asking which law enforcement agency Luma reported it to. Luma would not say. Today, I confirmed that Luma reported it to the FBI.

And this is important: at this time there does not appear to be any connection between the cyber attack, that Luma says it suffered, and the explosion/fire at the Monacillo plant, according to a source with direct knowledge of both investigations.