Three Atlantic City residents admitted Thursday that they abducted a teen mother from the resort in 2011, then killed her before dumping her body in the Schuylkill River.

Nadirah Ruffin, 19, was taken from the Back Maryland home of her cousin March 26, 2011, after she recognized the voice of one of three armed people with masks who barged into the apartment and duct-taped her and four other women in a robbery attempt.

Shamerria Smith, 26, Aziz Sanders, 20, and Deshawn Hicks, 21, each pleaded guilty to weapons charges in Camden federal court.

They each admitted to one count charging them with use of a firearm, and aiding and abetting the use of a firearm, in furtherance of a crime of violence. Because it is considered a federal Hobbs Act violation, they could face life in prison, according to Matthew Reilly, spokesman for the U.S. Attorney’s Office.

After Ruffin recognized Smith’s voice, the woman ordered Sanders to punch the teen, according to the admission in court. Smith then punched her, because she didn’t think Sanders struck the girl hard enough.

The three took Ruffin in their green van first to Clementon and then to Philadelphia.

But because Ruffin was the mother of a small boy, Smith said, she couldn’t shoot the girl, the charges state.

She then placed the gun near Sanders and told him that they were not leaving until someone else killed Ruffin. That’s when Sanders and Hicks took Ruffin to the banks of the Schuylkill River, where Sanders fatally shot her in the head. Her body was dumped in the river.

Ruffin’s body was found April 19, 2011, by a college rowing team.

The trio could have faced the death penalty because they were prosecuted under federal rather than state charges, but U.S. Attorney General Eric Holder recently made a decision not to seek capital punishment.

Three others involved in the planning and coverup of the crimes previously pleaded guilty.

The home where Ruffin had been staying was targeted in retaliation for the beating of Smith’s cousin, Isiah Ruffin, who was not related to the victim.

Isiah Ruffin was allegedly beaten by Donald Hawkins after Isiah allegedly made a pass at Hawkins’ girlfriend, Monica Dunn.

Dunn, Nadirah Ruffin’s cousin, lived in the North Maryland Avenue home where the abduction occurred. According to the federal complaint, Dunn was dealing woki, which is marijuana dipped in PCP or embalming fluid.

The three entered the home and Smith, Sanders and Hicks duct-taped Dunn, Ruffin and three other women. They took more than $500 and marijuana from the house and destroyed cellphones.

Then, Ruffin recognized Smith’s voice, the complaint states.

“Shamerria, why are you doing this to me?” she asked. “You know me.”

Smith’s reply, according to the complaint: “Now we got to take the (expletive)” and “Now we have to kill the (expletive).”

While the other three men who have pleaded guilty in the case have the same last name as the victim, they are not related.

Isiah Ruffin previously pleaded guilty to providing false statements to investigators about the home invasion and kidnapping. He is scheduled to be sentenced Oct. 23.

Isiah’s uncle Henry Ruffin, 42, of Gloucester County, and Smith’s father, Ronnie Ruffin, 43, formerly of Pleasantville, both pleaded guilty to failing to tell FBI special agents who interviewed them that they knew Smith, Sanders and Hicks were involved in the home invasion and kidnapping.

They each face three-year prison terms when they are sentenced in September.

Staff Writer Joel Landau contributed to this article.