Safety concerns regarding a Dupont home that caught fire early Wednesday, killing two tenants inside, are still under investigation. Police have identified Michael Patrick McLoughlin, 24, and recent Georgetown University graduate Nina Brekelmans, 25, as the two victims of the fire. (WUSA9)

Nina Brekelmans graduated from Georgetown University in May with a master’s degree in Arabic Studies, focused on women’s rights in the Arab world. The 25-year-old was headed to the Middle East to research Jordan’s female distance runners, combining two of her passions.

Michael Patrick McLoughlin, 24, graduated magna cum laude in 2012 from the University of Maryland with degrees in finance and economics. He channeled his enthusiasm into his work and play and surprised his bosses at an insurance company by turning around a complex spatial data analysis a month before it was due.

They rented living quarters on the upper floors of a rowhouse on Riggs Place NW, just off 16th Street and not far from Dupont Circle, that caught fire and burned early Wednesday. Both were killed. And friends, colleagues and families are mourning two young lives lost in what onlookers described as a terrifying early morning blaze. The incident remains under investigation.

McLoughlin’s family issued a brief statement, saying he “was just beginning his career in D.C. when this tragedy occurred. Michael was a driven, intelligent young man, with an amazing ability to make people laugh. We are devastated that he is gone. We miss him greatly.” Brekelmans’s immediate family asked for privacy; a longtime friend described her as “just extraordinary.”

D.C. police and fire officials, along with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, are investigating the 2:30 a.m. fire and said the cause has not been determined. But in a statement, Georgetown University said the fire started with an electrical malfunction. Lt. Sean Conboy, a spokesman for D.C. police, would say only that the cause does not appear suspicious. Three firefighters and two other occupants were injured.

Nina Brekelmans, near the Nile River in Egypt in 2010. (Family Photo)

Sefanit Befekadu, a spokeswoman for the D.C. Department of Consumer and Regulatory Affairs, said an inspection of the building the day of the fire revealed code violations, but city officials would not provide the report, citing the ongoing investigation. She did not say when the four-story rowhouse had last been inspected. A fire department spokesman was unable to say whether the house had working smoke detectors.

The building’s owner could not be reached to comment.

Just midway through her 20s, Brekelmans had built a résumé people twice her age might envy. She competed with the Georgetown Running Club, was treasurer of a women’s international organization and interned with Georgetown’s Muslim Chaplaincy. She was fluent in Arabic and Spanish and had studied in Jordan on a prestigious Boren Fellowship from the National Security Education Program.

“She was not one to sit there and flaunt her accomplishments,” said Mary Grace Pellegrini, who grew up with Brekelmans in Louis­ville and spent three years in high school with her there before both moved to the District. “She was extraordinarily accomplished and immensely humble.”

Brekelmans did her undergraduate work at Dartmouth College, where she was a walk-on to the cross-country and distance running programs. In 2012, she approached Jerry Alexander, coach of the Georgetown Running Club, made up mostly of accomplished runners who were in competitive college sports. Brekelmans knew that she was behind others, who ran up to 70 miles each week.

“She wanted the opportunity to get better,” said Alexander, 51, a lawyer with the U.S. Department of Justice’s civil division. “She knew she would be coming into the situation where she wasn’t at the top. She said she was a hard worker and would we give her the chance to prove herself.”

Brekelmans won her first half marathon last year in Jordan, on a course near the Dead Sea, Alexander said. There, she trained every day at 4:30 a.m. to beat the heat and avoid any problems in a country where the sight of a woman in shorts might prompt anger. It was just the sort of topic she planned to explore when she returned there on a Fulbright grant.

Michael McLoughlin was passionate about his work but knew how to have fun. (Family Photo)

Fida Adely, an associate professor at Georgetown, said Brekelmans had combined her passion for the Arabic language and running as she set out to find ways that athletics could become “a tool to enhance the lives of girls and young women in the Arab world.”

“While she could be quiet, she was thoughtful and really strove to understand the complex theories and realities of the region of the world she so loved,” Adely said. She said friends in Jordan are planning a memorial event.

Brekelmans moved into the Dupont Circle area house from Upper Northwest before the start of the school year in part to take advantage of theater and dining opportunities and to spend time with friends as she finished her graduate studies.

Pellegrini last saw her friend at the May 15 graduation, when they celebrated at dinner. They made plans to attend a play at a Jewish community center near her house on Wednesday and had confirmed the get-together in an e-mail over the weekend.

“I sensed something was up when I didn’t hear from Nina and she didn’t show up,” Pellegrini said. “That was not like her.”

The Muslim chaplain at Georgetown described Brekelmans as a “woman of faith in a loving God, faith in herself and in people. She believed that dreaming big is possible. . . . She was very humble, very loving and the best listener ever.”

McLoughlin, who grew up in Leonardtown in Southern Maryland, was passionate about his work but also knew how to have fun. He had moved into the Riggs Place house just two months ago while he was working at United Educators, an insurance company in Bethesda.

“Mike was mature beyond his years,” said Greg Peed, an actuarial analyst. “He had a quick grasp of the terminology used here and completed a complex project — a spatial data analysis — a month ahead of schedule. He had an inquisitive nature and was not shy about asking questions.”

McLoughlin had begun his career interning at OST Global Solutions, a consulting company in Rockville that helps contractors write proposals to win government jobs. His boss, Alex Brown, said he was so impressed by McLoughlin’s thorough research and quick grasp of the field that he hired him full-time.

Brown said that McLoughlin balanced professionalism and fun. “He was hysterical,” he said. “His goal was always to make sure that everyone else around him was happy.”

Once, he helped push Brown’s gasless car out of the street, drove him to get gas and drove him back, despite work piling up on his desk.

Leah Regan met McLoughlin when they interned at Global Solutions. At first, she thought him so serious that he was intimidating. Then she discovered his other side.

“He’d go from being incredibly professional on a conference call to five minutes later guffawing with laughter,” Regan said. She invited fellow interns to her house for a weekly dinner, where McLoughlin made sure that they turned on a sports game every week.

“He wasn’t able to sit down,” Regan said. “If the ball was in play, he was pacing around my living room, screaming at the top of his lungs in sheer excitement at the fact that sports was happening. . . . Most of us enjoyed watching Mike react to sports more than we actually enjoyed whatever sport was being broadcast.”

McLoughlin wore old-fashioned red headphones everywhere he went and could scarf down three helpings of food before anyone else had finished a first serving, friends said. And he would lean so far off a couch that he seemed in danger of falling off. “He was so animated, and he was so passionate,” Regan said.

Dana Hedgpeth, Magda Jean-Louis, Jennifer Jenkins, Susan Svrluga and Clarence Williams contributed to this article.