British police said Friday there was no indication of foul play in the fire that shut down Heathrow Airport, but they confirmed counterterrorism officers are leading the investigation due to the critical nature of the incident.
The fire erupted at an electrical substation in Hayes, causing a mass power outage and halting all operations at the UK's busiest airport.
According to the authorities, the involvement of counterterrorism police was standard for incidents of national infrastructure disruption, adding that all possibilities remained under review.