Aneela Abad, general secretary at the Islamic Center of New Mexico, described a community reeling from the killings, its grief compounded by confusion and fear of what may follow.
"We are just completely shocked and still trying to comprehend and understand what happened, how and why," she said.
Some people have avoided going out unless "absolutely necessary," and some Muslim university students have been wondering whether it is safe for them to stay in the city, she said. The center has also beefed up its security.
Police initially said the same vehicle was suspected of being used in all four homicides - a dark gray or silver four-door Volkswagen that appeared to be a Jetta or Passat with dark tinted windows. But the police chief's tweet referred only to the vehicle's connection with one slaying.
Authorities released photos hoping people could help identify the car and offered a $20,000 reward for information leading to an arrest.
Investigators did not say where the images were taken or what led them to suspect the car was involved in the slayings. Police spokesperson Gilbert Gallegos said in an email Monday that the agency has received tips regarding the car but did not elaborate.
Gallegos said he could not comment on what kind of gun was used in the shootings, or whether police know how many suspects were involved in the violence.
Few anti-Muslim hate crimes have been recorded in Albuquerque over the last five years, according to FBI data cited by Brian Levin, director of the Center for the Study of Hate and Extremism and a professor of criminal justice at California State University at San Bernardino.
From 2017 through 2020, there was one anti-Muslim hate crime a year. The highest recent number was in 2016, when Albuquerque police recorded six out of a total of 25 hate crimes.
That largely tracks with national trends, which hit the lowest numbers in a decade in 2020, only to increase by 45% in 2021 in a dozen cities and states, Levin said.
Albuquerque authorities say they cannot determine if the slayings were hate crimes until they have identified a suspect and a motive.
It was not clear whether the victims knew their attacker or attackers.
The most recent victim was found dead after police received a call of a shooting. Authorities declined to say whether the killing was carried out in a way similar to the other deaths.
Muhammad Afzaal Hussain had worked as a field organizer for a local congresswoman's campaign.
Democratic Rep. Melanie Stansbury issued a statement praising him as "one of the kindest and hardest working people" she has ever known. She said the urban planner was "committed to making our public spaces work for every person and cleaning up legacy pollution."
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As land-use director for the city of Espanola - more than 85 miles (137 kilometers) north of Albuquerque - Hussain worked to improve conditions and inclusivity for disadvantaged minorities, the mayor's office said.