US police hunting the killer of four Muslim men in a New Mexico city said Tuesday they have arrested their "primary suspect" and charged him with two of the murders.
The killings, three of which came in the last couple of weeks, had sent shock waves through the Muslim population in Albuquerque, with community leaders talking of a growing sense of panic.

But on Tuesday, investigators said a public tip had led them to 51-year-old Afghan immigrant Muhammad Syed.

The breakthrough came after detectives had appealed for public help cracking the case, issuing a photograph of a car they believed was involved in the killings of the South Asian men, two from Pakistan.

"We tracked down the vehicle believed to be involved in a recent murder of a Muslim man in Albuquerque," Albuquerque police chief Harold Medina wrote on Twitter.

"The driver was detained and he is our primary suspect for the murders."

The New York Times cited Ahmad Assed, the president of the Islamic Center of New Mexico, saying he had been told the suspect was a Sunni Muslim who was angry that his daughter had married a Shiite Muslim.

Shiite and Sunni are the two main branches in Islam. The schism that opened around 1,400 years ago over who should succeed the Prophet Mohammed continues to affect intra-Muslim relations around the world.

At a press conference, police said they were still investigating the motive.

Tensions rose in Albuquerque after the discovery on August 5 of a body near an office providing services to refugees.

That came as police were investigating the deaths of two men who had died within the previous 10 days. It is these two murders that Syed has been charged with.

A gun believed to have been used in the slayings was found during a police search of his home.

The November death of an Afghan man in the city was also being probed for a likely connection to the recent killings.

The spate of killings had set nerves on edge in the city's Muslim community.

"Now, people are beginning to panic," Tahir Gauba, the director of public affairs with the Islamic Center of New Mexico, told the Albuquerque Journal earlier.

US President Joe Biden weighed in over the weekend, pledging unity and support.

"I am angered and saddened by the horrific killings of four Muslim men in Albuquerque," he said on Twitter.

"While we await a full investigation, my prayers are with the victims' families, and my Administration stands strongly with the Muslim community.

"These hateful attacks have no place in America."