(NewsNation) — The brother of one of the four Muslim men murdered in New Mexico over the last year is pleading with police to find the killer.

“I have to cry right now every day without him,” Sharief Hadi, brother of murdered Mohammad Ahmadi said while fighting through tears. “What kind of life is that? What is happening?”

Ahmadi was killed in November while working at the store he owned with Hadi, 62, in the Albuquerque area. Hadi said he moved to the United States from Afghanistan to start a new life.

“I have to go there every day. Every minute,” Hadi said. “We came to the United States to live in peace but I haven’t seen any peace here.”

Police officially linked the string of killings together Monday, with Albuquerque Mayor Tim Keller saying there was “a very, very strong link.”

The most recent killing happened Friday night, when a man was ambushed and shot, KRQE reported. The man who KRQE identified as Naeem Hussain, was found dead after police received a call of a shooting. The other two victims — Muhammed Afzaal Hussain, 27, and Aftab Hussein, 41 — were killed in the past week, and both were from Pakistan and members of the same mosque.

Police released a photo of a vehicle they say is involved in the killings: a dark gray or silver Volkswagen sedan, a Jetta or Passat, with tinted windows. The photo highlights possible damage to the front driver’s side wheel and rear driver’s side wheel and fender.

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.

The killings have sent ripples of fear through Islamic communities in New Mexico and beyond and fueled a race to find who was responsible. Keller said the killings are keeping the Muslim community from functioning normally.

“Members of our Muslim community who are afraid to participate in everyday activities that they should never be afraid to do things like shopping, things like praying things, like going to school,” Keller said.

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.

Albuquerque authorities say they cannot determine if the slayings were hate crimes until they have identified a suspect and a motive. Officials have not determined if one or more people are involved in the killings.

The Associated Press contributed to this report.

Interviews have been edited for length and clarity.