Northern Virginia officials are raising questions about how Verizon handled the loss of several 9-1-1 emergency systems, The Washington Post reported Tuesday. Verizon operates the emergency service.

The director of Fairfax County’s emergency communications center said that it took Verizon roughly three hours to officially notify the county that 911 was down after the emergency line went out at 6:30 a.m. Saturday, the Post reported.

In addition to Fairfax County, Prince William County and Manassas Park officials are asking Verizon to conduct an internal investigation, Manassas Park Patch reported earlier this week. 

The 911 problems in Arlington, Fairfax County, Prince William County and elsewhere started in the aftermath of Friday night's derecho and were not fully cleared up until Tuesday in some areas. The main culprit seems to have been a Verizon "trunk line" in Arlington, Patch reported Saturday. A trunk is a "communications path connecting two switching systems in a network" — a key element in routing calls, according to this Verizon glossary.

Manassas Park Mayor Frank Jones said earlier this week, " ... Personally, I am extremely concerned. We cannot have the critical link between the citizens and the city's emergency response capability compromised. The lack of information, the duration of the outage, and the clear lack of back-up/redundancy have created an unacceptable situation. I agree with (Fairfax County Supervisor) Sharon Bulova—an investigation is warranted."

9-1-1 emergency service was finally completely restored in Fairfax about noon Tuesday.