File: D.C. firefighters tried to extinguish a house fire on Isherwood St. NE, that took place after the home exploded on June 4, 2014 in Washington, D.C. (Ricky Carioti/The Washington Post)

A 46-year-old man who died when the Northeast Washington condominium building he lived in exploded in flames June 4 set the fire himself in what D.C. police said Monday has been ruled a suicide.

The afternoon explosion and fire, which went to two alarms, nearly leveled the four-unit building in the 1600 block of Isherwood Street NE, on the eastern edge of Capitol Hill. Chris J. Christofi, who had lived there 10 years, was killed in his ground-floor apartment. His body was not recovered from the debris until two days later.

Because of the intensity of the fire and the explosion, the case was investigated by both the D.C. fire department and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. Washington Gas said that the building was fed only by electricity but that it had repaired a gas leak in an adjacent house the previous month.

Two D.C. police officials said gasoline was used to set the building on fire.

Family and colleagues at the downtown Washington lobbying firm where Christofi worked as an office manager said he left the office early on June 4 and was seen by neighbors walking his pet bull dog, Bella, about two hours before the fire started about 3:45 p.m.

Co-workers at the firm, Venn Strategies, and at a nonprofit where he had previously worked described Christofi as a dedicated worker who fought hard for those he supervised and was credited with innovations that made the offices more productive. They also described him as a private person who loved his pet and was a BMW car enthusiast.

Christofi’s sister, Maria Christofi Georges, visited the fire scene and talked to neighbors to learn about what had happened. One said she saw Christofi and his dog in a doorway as flames engulfed the building and buried both in rubble.

Get updates on your area delivered via e-mail