Margaret Sanchez, bleary-eyed and distant, sat in a Jefferson Parish courtroom Monday and pleaded not guilty to charges that she and her boyfriend fatally stabbed and then carved up Bourbon Street dancer Jaren Lockhart before dumping the mutilated remains into the Gulf of Mexico two years ago.

Her demeanor — first smiling shyly, then teary-eyed, then simply staring out the window — was apparently different than it was the night Lockhart disappeared, according to a recent search warrant.

Detectives investigating the case have said they don’t know exactly what happened among Lockhart, Sanchez and Terry Speaks, the second suspect, once the three arrived at a home Sanchez and Speaks shared in the 2000 block of Connecticut Street in Kenner.

They also are not certain about a motive for Lockhart’s death.

But a warrant that seeks permission for State Police to search a cellphone says that Sanchez and Speaks “were involved in ritualistic sexual activities” and used the phone to record the acts — presumably also whatever happened with Lockhart.

Sanchez, 30, and Speaks, 40, picked up Lockhart on June 6, 2012, from Temptations, the Bourbon Street club where she danced. Surveillance footage showed the 22-year-old mother of a little girl leaving the club with two people. Earlier, she had told co-workers she was “going to make rent” by dancing at a “private party,” according to the warrant.

During the investigation, several people, including a doorman at Temptations, identified the man Lockhart left with as “Allen Rice,” an employee of Stilettos, a neighboring strip joint, and the woman as his girlfriend or wife.

Days later, after the footage was aired on local TV and posted on local news websites in an effort to identify the people last seen with Lockhart, Sanchez’s brother called Kenner police and told them that the woman was his sister and the man was her husband, “Allen Sanchez.”

Sanchez’s mother told police she was “positive” the people were her daughter and a man she knew as “Allen Rice.”

A woman who recently answered the door at a Metairie home listed in court documents as Sanchez’s address, and where she was arrested, said a reporter had the wrong address and refused to comment.

Investigators began to close in on Sanchez and Speaks as suspects after license-plate recognition cameras spotted a green 2001 Chevrolet Lumina leaving Louisiana and entering Mississippi on June 6, 2012. The next day, parts of Lockhart’s body began to wash ashore in Bay St. Louis and Pass Christian, Mississippi.

Sanchez and Speaks were pulled over six days later in the Chevrolet in Tangipahoa Parish and booked on unrelated charges.

At that point, investigators learned that Speaks used the alias “Allen Rice.”

Sanchez was arrested May 7 in connection with Lockhart’s death.

Speaks, 40, a convicted sex offender, is being held in federal prison in New York on an unrelated charge. His sentence there is set to expire in the fall, when he will be extradited to Jefferson Parish, according to the Kenner Police Department, which is in charge of the investigation.

According to a Jefferson Parish arrest log, Speaks has allegedly admitted that he and Sanchez killed “a girl” in Louisiana, cut up her body and dumped the remains over a bridge in coastal Mississippi so they could not be found.

That statement was revealed in a brief summary of the case included in the arrest log filed after Sanchez was booked into the Jefferson Parish Correctional Center. It is not clear to whom Speaks allegedly made the statement about the stabbing death, but Kenner police had traveled to New York to interview him after they took over the investigation from the Hancock County Sheriff’s Office in Mississippi.

Sanchez and Speaks each face charges of second-degree murder, obstruction of justice and conspiracy to obstruct justice.

Kenner police have said they believe Sanchez helped to cut up the body before dumping the pieces off a bridge in Mississippi. The alleged dismembering led to the obstruction charge.

On Monday, Sanchez smiled a few times after taking her place with other inmates who were being processed, but by the time 24th Judicial District Judge Stephen Grefer asked whether she was pleading not guilty to the charges, she was teary-eyed and said only, “Yes.”

She otherwise spent the hearing rubbing her eyes with her shackled hands.

Sanchez will return to court on Oct. 15 for a status hearing, when Speaks is expected to join her for his arraignment.

Staff writer Jim Mustian contributed to this report.