Police believe the son of the prime suspect in the killings of four Muslim men may have played a role in the murders, which have shaken the American Muslim community in New Mexico's largest city.

Cellphone data shows Shaheen Syed, 21, was in the same “general area” of Albuquerque as his father at the time of the August 5 killing of 25-year-old trucking entrepreneur Naeem Hussain, according to a filing by federal prosecutors for a Monday detention hearing during which Shaheen was denied bail.

His attorney John Anderson said the allegations were “exceedingly thin and speculative”.

Police last week charged Shaheen's father, Muhammad Syed, 51, with two of the murders and linked the four killings to personal grudges, possibly fueled by intra-Muslim sectarian hatred.

Shaheen was arrested last week on federal firearms charges for providing a false address.

“Law enforcement officers also have recently discovered evidence that appears to tie the defendant, Shaheen Syed, to these killings,” the filing said.

Agents believe Shaheen observed Naeem leaving an Aug 5 funeral service for two of the murdered Muslim men, based on FBI analysis of cell tower data. He then followed him to the area of a parking lot where Naeem was shot dead.

“Telephone calls between Muhammad Atif Syed and the defendant (Shaheen Syed) would be consistent with quick surveillance calls, both before and after the shooting,” the filing said.

Prosecutors did not provide evidence on the other shootings.

Imtiaz Hussain said he believed at least two people were involved in the Aug 1 murder of his brother Muhammad Afzaal Hussain.

A pistol and rifle were used to shoot Afzaal, a city planning director, 15 times in around 15 to 20 seconds, according to police records and Imtiaz.

For one suspect it is difficult to use two weapons in that short an interval, said Imtiaz.

The victims, Naeem and Afzaal, were not related.

Muhammad, an Afghan refugee, has been charged with killing Afzaal, who was from Pakistan, and cafe manager Aftab Hussein, 41, who had ties to Afghanistan and Pakistan.

A fourth man, supermarket owner Mohammad Ahmadi, 62, was shot dead on November 7, 2021.

Police have said they are working with prosecutors on potential charges for the murders of Naeem and Ahmadi.