Three teenagers were arrested Wednesday on murder and arson charges stemming from a house fire in Denver over the summer that killed five immigrants from Senegal, a crime that drew the attention of that country’s president, the authorities said.
The names of the three boys were not released because of their ages — two of them are 16, and one is 15, according to the police, who said investigators were limited in their ability to share information about the case because it involved minors.
At a news conference announcing the arrests, officials said that while there was no indication that the fatal arson constituted a hate crime, solving the case had been a top law enforcement priority.
They declined to discuss a motive for the arson or say how the three teenagers in custody had been identified or how the fire had been set. But they noted that the federal Bureau of Alcohol, Tobacco, Firearms and Explosives and the Secret Service had assisted in the investigation.
Mayor Michael B. Hancock of Denver said he could not recall attending a police news conference to announce arrests during his 10 years in office.
“But this was one of the most heinous crimes I’ve ever seen or witnessed in our city, as mayor or otherwise,” Mr. Hancock said. “It also hit me to the core. Many of us, if not all of us, have wondered to ourselves and out loud, who could commit such a crime to such a beautiful family?”
In the early morning of Aug. 5, the fire consumed a two-story home in the Green Valley Ranch neighborhood in northeastern Denver. Killed in the blaze were Djibril and Adja Diol and their daughter Khadija, 2, as well as Mr. Diol’s sister Hassan Diol and her infant daughter, Hawa Baye, the authorities said.
Later that day, fire officials made a startling revelation: They said that the blaze appeared to have been intentionally set. Three other people who were inside the house were able to escape the fire by jumping from the second floor, fire officials said at the time.
Papa Dia, a Senegalese community leader and a spokesman for the family of the victims, said at Wednesday’s news conference that the arrests had brought a measure of relief.
“At some point, we lost hope,” Mr. Dia said. “We were afraid that this could become a cold case.”
There are about 2,000 immigrants from Senegal in the greater Denver area, according to Mr. Dia. He said that the arson did not define the state of Colorado.
“As you know, we are immigrants that came all the way from Africa to seek opportunity in this great nation,” he said. “It’s so sad that part of our community members, in that process of seeking that opportunity, their life was tragically taken.”
A day after the fire, President Macky Sall of Senegal mourned the deaths of the five immigrants from his country and said that he was closely monitoring the situation. The consul general of Senegal visited Colorado after the fire, which Islamic American groups said at the time should be investigated as a hate crime.
Later that month, the police released an image of three people in dark hoods and white masks, along with photographs of a dark-colored four-door sedan in which the masked people were believed to have fled. Rewards were offered for information leading to an arrest.
The three teenagers face 28 criminal counts that include first-degree murder, first-degree attempted murder with extreme indifference, first-degree arson and first-degree burglary, the police said.
Paul M. Pazen, the Denver police chief, said on Wednesday that he did not want to compromise the case by releasing details about what had led to the arrests.
“We have a good understanding of the hows and whys on this,” he said.