(NewsNation) — Federal authorities have arrested the son of a man who is charged with killing at least two of the four Muslim slain in a string of homicides in New Mexico.

In a criminal complaint filed this week, prosecutors allege that Shaheen Syed lied about his address when purchasing a firearm and knew more about the killings than he let on. His father, Muhammad Syed, has been charged with killing two of the four men.

Muhammed Syed has been arrested for the murders of Aftab Hussein, 41, and Muhammad Afzaal Hussain, 27. Police believe Syed may also have killed Mohammad Ahmadi, 62 and Naeem Hussain, 25.

Albuquerque Police Chief Harold Medina said last week it was not clear yet whether the deaths should be classified as hate crimes or serial killings or both.

Prosecutors are seeking to detain the younger Syed, alleging he poses a flight risk and is a grave danger to the community. In a motion filed Friday, prosecutors said Syed was with his father when they purchased two firearms, as well as a mount and scope for one of the rifles used in the shootings.

Investigators also determined that cellphone tower data put Shaheen Syed in the area near where Haeem Hussain was killed.

Investigators believe the murders may have been linked to a conflict Muhammad Syed had with some of the victims. He denied any connection to the murders and told authorities he was so unnerved by the violence he was exploring moving his family to Houston.

Syed’s daughter believes her father is innocent.

“I know he is in custody but I don’t think it is true,” Lubna Syed told NewsNation affiliate KRQE.