Washington Post photojournalist and three-time Pulitzer Prize winner Michel du Cille died Thursday while on an assignment in Liberia. He died at the age of 58.

He was hiking from a village in the Salala district of Bong County in Liberia after working on a project, and he collapsed. Dr. du Cille was taken to a nearby clinic, but had to be transported to a hospital two hours from the clinic. He was pronounced dead upon arrival due to an apparent heart attack.

Washington Post executive editor Martin Baron expressed his grief in a statement to The Post’s staff. He said that he was “deeply saddened” to announce Michel du Cille’s death while “documenting the tragedy of Ebola.” Baron said he was heartbroken and called Michel du Cille one of the “world’s most accomplished photographers.”

Baron added that du Cille was devoted to his work, especially his current Ebola project, despite the risks. Baron said “that is the sort of courage and passion” he displayed throughout his time as a photojournalist.

His assignment was to cover the plight of Ebola patients and their caretakers. While in Liberia, he dressed in protective gear from head to toe and rigorously scrubbed with chlorine. He wore rubber gloves while operating his camera. He was able to get in close proximity with Ebola patients, and he also grew close with the family members of the victims.

He explained that being with the patients and their families was an emotional experience. “It is profoundly difficult not to be a feeling human being while covering the Ebola crisis,” du Cille wrote in The Post in October. He said that the scenes were gruesome because they could not be sanitized. However, du Cille wanted the world to see the “dehumanizing effects” of the Ebola virus. He said that the story had to be told, so he avoided extreme intrusion and moved “gingerly.”

Du Cille was awarded the Pulitzer Prize three times for his photos of “human struggle and triumph.” In the 1980s, he won two Pulitzer Prizes for photography with the Miami Herald for photographs of the devastation caused by the eruption of the Nevado del Ruiz volcano in Colombia and photographs of the subsequent rehabilitation of a housing project overrun by the drug crack. In 1988, he started working for The Post. He shared his third award with Anne Hull and Dana Priest, reporters for The Post, in 2008 for their investigation on the treatment of Walter Reed Army Medical Center military veterans.

Du Cille become the director of photography at The Post in 2007. However, he went back in the field full-time as a photojournalist in 2012 and continued to capture the story of humanity in dire circumstances. His assignments took him from Sudan and other African countries to Afghanistan. He even came under fire in Afghanistan in 2013. He stressed the importance of journalists always showing the raw truth.

Du Cille’s most recent work on Ebola in Liberia was published on Dec. 7. He was married to Nikki Kahn, who was also a photographer at The Post, and he had two children from a different marriage.