Santa Ana winds have died down across the greater Los Angeles area, helping firefighters to bring almost 40,000 acres of ongoing wildfires under control.

A law enforcement task force has been set up to uncover what caused the fires. The local agencies involved — the Los Angeles fire and police departments and the county Sheriff’s Department, as well as Cal Fire — are considered to be among the most skilled in the country. The Bureau of Alcohol, Tobacco, Firearms and Explosives is leading the probe.

Dozens of people are believed to have died in the Palisades and Eaton fires, which have burned down whole swaths of communities