Another life has been added to the death toll of the Wildland Fire Service’s first fatal incident.

The Department of the Interior on Friday announced that 43-year-old Nathan Matthews of Lincoln, Nebraska, died from the injuries he sustained while fighting the Knowles Fire near the Colorado-Utah border on June 27. Officials said he was assigned to the Rifle Helitack crew when he was severely injured during a burnover and was hospitalized for nearly a month before he died.

“This is another heartbreaking loss for our wildland fire family,” U.S. Wildland Fire Service Chief Brian Fennessy said in a press release. “We mourn the loss of Nate while continuing to grieve the deaths of Emily, Nick and Sydney. Our hearts are with their families, friends, crewmates and everyone impacted by this tragedy. We remain committed to supporting those affected and honoring the legacy of all four firefighters who made the ultimate sacrifice in service to our nation.”

PREVIOUS COVERAGE: Identities of firefighters killed by burnover near Colorado-Utah border released

Three other firefighters, 38-year-old Emily Barker of Michigan, 27-year old Nick Hutcherson of Arizona; and 27-year-old Sydney Watson of Alabama, died at the scene.

Officials said a fifth firefighter was also treated for burns after the burnover, but they have not shared their identity nor their health status. Officials have also not shared further details of the events leading up to the burnover and the firefighters’ positioning.

:A serious accident investigation team continues to review the circumstances surrounding the incident,” officials said. “Information regarding memorial services for Nate will be released at a later date.”