Attorneys for Lindsay Clancy are asking a judge to examine the conduct of the lone juror who favored convicting the Massachusetts mother in the deaths of her three children. Her legal team is also seeking dismissal of the criminal case, arguing that holding another trial would violate her constitutional protection against double jeopardy.

In a motion filed Friday and released publicly Monday, Clancy’s attorneys asked the court to question the juror about several matters. They want to know whether he used a cellphone during deliberations, whether he was truthful on the questionnaire completed by prospective jurors before trial and whether he gave accurate answers when the judge questioned jurors the day before proceedings concluded.

The judge declared a mistrial Sept. 4 after the jury reported that it remained unable to reach a unanimous decision, despite deliberating for several days. Eleven of the 12 jurors were prepared to find Clancy not criminally responsible, with most believing she was experiencing postpartum psychosis when she strangled her children — 5-year-old Cora, 3-year-old Dawson and 8-month-old Callan. The lone holdout, Michael Desronvil, agreed with prosecutors, who maintained that Clancy understood what she was doing.

Among the requests made by Clancy’s attorney, Kevin Reddington, was an order seeking records of any calls or text messages Desronvil made between 8 a.m. and 4:30 p.m. on each day of jury deliberations. Cellphone use during deliberations is prohibited in Massachusetts.

Prosecutors have not said whether they intend to retry Clancy. She remains charged with murder and is being held in a psychiatric hospital while the case proceeds.

In a separate motion filed Monday, Clancy’s lawyers asked the judge to take the unusual step of ending the criminal case instead of ordering a retrial. They argued that the mistrial should never have been declared.

The attorneys contend that the judge should have replaced the holdout juror with an alternate after the jury foreperson reported that a juror was refusing to follow the law governing reasonable doubt.

“Ms. Clancy, like all criminal defendants, had a Constitutional right to have her fate decided by an impartial jury of her peers, faithfully applying the law as instructed rather than superimposing the juror’s own view of legal right and wrong, including the foundational principle that, absent proof beyond a reasonable doubt of her guilt, she must be acquitted,” her attorneys wrote in the motion to dismiss. “The multiple reports of a juror violating this bedrock principle, therefore, required a judicial inquiry sufficient to ascertain whether her right to an impartial jury was being violated.”

A spokesperson for Plymouth County District Attorney Timothy Cruz declined to comment on the motions.

Desronvil has not been accused of wrongdoing related to his jury service. Other jurors did, however, complain that he held an inflexible belief that Clancy was guilty.

In a statement issued through his attorney last week, Edward Paltzik, Desronvil said he “didn’t have any doubts” that Clancy understood what she was doing when she killed her three children.

“As I tried to explain different possible theories during deliberation, I kept getting cut off as if I had doubts based on the evidence present,” he said.

“Based on all the physical evidence, key witnesses, and what the prosecution presents, I thought it was enough proof that she knew exactly what she was doing and planned,” the statement said.

Reddington filed the motions as Clancy’s former husband, Patrick Clancy, appeared in an interview with “60 Minutes” to discuss the illness he believes his then-wife was experiencing when she killed their children.

During the interview, correspondent Ross Douthat asked Patrick Clancy how concepts such as accountability and justice should be understood when mental illness is involved. “I think we can find a compassionate way to deal with these tragedies,” he replied.

“And that, that doesn’t mean no accountability,” Patrick Clancy said. “It just means that we recognize the suffering and the stigma, and we try to find a way to prevent this from happening in the future. That’s always how I’ve looked at it.”