A Breaux Bridge woman Tuesday admitted to a judge that she was one of two people who strangled her elderly mother in 2011, drove her body to Lake Martin and left it in a car for others to find.

Heller Marie Dupuis, 51, pleaded guilty to manslaughter in the November 2011 killing of 83-year-old Jessie B. Messex, whose body police found with the rope still around her neck.

Dupuis acknowledged to 16th District Judge Lori Landry on Tuesday that she and an accomplice, her 33-year-old daughter, Toni Marie Dupuis, carried out the crime.

Heller Dupuis in open court Tuesday did not say why they killed Messex.

“During the late hours of Nov. 16, 2011, or the early morning hours of Nov. 17, 2011, Heller Marie Dupuis and Toni Dupuis strangled Heller’s mother … while she lay helpless in bed,” prosecutor Chester Cedars, reading from a court filing, said.

Messex was recovering from a stroke and had her daughter and granddaughter living with her and caring for her at Messex’s North Berard Street home in Breaux Bridge, said Cedars, an assistant district attorney for the 16th court district.

Heller Dupuis faces up to 40 years in prison at hard labor on the manslaughter conviction. Landry set Heller Dupuis’ sentencing for March 13.

Toni Dupuis also has agreed to plead guilty to manslaughter, though no court date has been scheduled.

The manslaughter conviction and its 40-year maximum sentence is far less punishment than Cedars had wanted for the defendants. In 2012, both Heller Dupuis and Toni Dupuis were charged with first-degree murder, and the 16th Judicial District Attorney’s Office was seeking the death penalty.

Later evaluations found the women were not intellectually and emotionally fit enough to be tried in a death penalty case, though prosecutors continued to push for life in prison, an automatic sentence in both first-degree and second-degree murder convictions. Then, late last year the Dupuises’ attorney, Craig Colwart, resigned from the Public Defender’s Office for the three-parish 16th Judicial District, which he ran for 20 years.

Cedars said the defender board recently decided Colwart would not continue as the women’s attorney. Cedars said it would take an attorney new to the case at least a year to catch up to prepare for a first-degree murder trial, and that dropping the charge’s severity level for a quicker prison sentence was what Messex’s family members wanted.

“In this business you have to work within the parameters that circumstances dictate,” Cedars said. “I’m not completely comfortable, however this particular case is not about me. It’s about realizing an acceptable degree of justice.”

Sitting in the courtroom gallery Tuesday were three members of Messex’s family. One of them was Estelle Malagarie, who was Messex’s daughter and is Heller Dupuis’ half-sister. Malagarie said the family didn’t want to comment until after Toni Dupuis pleads guilty or stands trial.

A few days after Messex’s death in November 2011, Malagarie told The Advocate that her mother was a “spunky” woman with a beautiful voice who “played the heck out of a clarinet.” Malagarie said at the time that she didn’t know why her sister and niece killed Messex. “I guess they didn’t agree on something and it busted loose,” Malagarie said.

Cedars said he would argue at Heller Dupuis’ sentencing hearing for the stiffest sentence possible, a prison term that approached the maximum 40 years for a manslaughter conviction.

“My focus will be to present a compelling case which would bring the maximum sentence allowed by law,” Cedars said.