Albuquerque Welcomed Muslims. Then Four of Them Were Killed.

Indeed, the killings have jolted an increasingly diverse city, where immigration, largely from Mexico and other Latin American countries, is a major source of population growth and integral to the city’s history. Immigrants from the Middle East, including Muslims and Christians from Lebanon and Syria, put down stakes in Albuquerque and other parts of New Mexico in the late 19th century.

The city gradually saw a new wave of Muslim immigrants in recent decades, with many coming to study at the University of New Mexico. A group of Muslim students came together in the mid-1980s to form the Islamic Center of New Mexico, which the three most recent victims attended.

Many in the city’s Muslim community come from Pakistan and Afghanistan, while others are from countries including India, Turkey, Syria, Iraq and Sri Lanka. During the Trump administration, when concerns grew over bigotry directed against Muslims, officials passed a bill affirming Albuquerque’s status as an “immigrant friendly” city. It restricted federal immigration agents from entering city-operated facilities and city employees from collecting immigration status information.

At least 300 Afghan refugees have arrived in Albuquerque over the past year, bolstering a growing community reflected today by at least eight different places of worship for Muslims. Albuquerque strengthened outreach efforts through translators speaking Arabic, Dari, Farsi, Urdu and Pashto — languages that officials have prioritized in recent days when sharing information about the killings.

Although Muslims in the United States faced violence and discrimination after Sept. 11 and during Donald J. Trump’s presidential campaign, the apparent serial nature of the attacks in Albuquerque — and the stubborn mystery of who is responsible — is uniquely disconcerting, said Sumayyah Waheed, senior policy counsel at Muslim Advocates, a civil rights group.

“I can’t think of any incident like this,” she said.

Ms. Waheed said it was concerning that the police in Albuquerque had apparently made a possible connection between the attacks only after three Muslim men were killed.