Greensboro, N.C. — Federal prosecutors say Demario James Atwater fired the final shot that killed the University of North Carolina at Chapel Hill's student body president nearly a year ago.

In a notice of intent to seek the death penalty, prosecutors said Eve Marie Carson was "particularly vulnerable" when Atwater "fired a single shotgun round from close range through the victim's hand and into her brain."

She had already been wounded by four small-caliber gunshots, the notice said.

Prosecutors filed the notice Friday in U.S District Court.

It does not indicate whether investigators believe Atwater might have fired any of the other shots. According to Chapel Hill police search warrants returned last June, investigators believe both Atwater and Laurence Alvin Lovette Jr. shot Carson.

An autopsy found Carson, 22, was shot with a shotgun to the right temple and also sustained a wound to her right hand – likely because she had raised her right arm to protect herself.

Atwater, 22, was indicted in October on a federal carjacking charge resulting in death in connection with Carson's slaying.

Last month, federal prosecutors announced they would seek the death penalty if he is convicted.

Chapel Hill investigators believe Atwater and Lovette, 18, kidnapped Carson and forced her to withdraw $1,400 from ATMs before killing her in the early morning of March 5.

Police found her body in a neighborhood several blocks from the UNC campus while responding to reports of gunshots.

According to Friday's filing, which outlines the federal government's reasoning for seeking the death penalty, Atwater killed Carson "to eliminate her as a possible witness to other offenses, including, at least, kidnapping, carjacking and robbery."

Orange County District Attorney Jim Woodall has said he is also seeking the death penalty for Atwater on state charges, which include first-degree murder, robbery and kidnapping.

It's still unclear whether Lovette will face any federal charges.

Because he was under age 18 at the time of the crime of which he is accused, a U.S. Supreme Court ruling makes him ineligible for the death penalty.