WOBURN — Lawyers for Irish nanny Aisling McCarthy Brady are accusing Middlesex prosecutors of acting unethically in the way they presented evidence to the grand jury that indicted her on a murder charge in the death of Rehma Sabir when the 1-year-old girl was solely in her care.
Defense lawyers also contend in court papers that the case put together by Middlesex District Attorney Marian T. Ryan’s office is so weak that it did not meet the low legal threshold of probable cause that is needed before Brady could be accused of committing any crime.
Attorneys for the Quincy nanny want a judge to dismiss the charges of first-degree murder and assault and battery on a child causing serious bodily injury.
In a statement issued Wednesday, Ryan said that her office is working on a response to the defense allegations, which they will soon file in court.
“This motion filing by the defense is the standard course of action in this type of criminal proceeding,’’ Ryan said in the statement. “We are in the process of drafting our response, and we will be prepared to fully argue the motion at the next hearing.’’
One defense motion calls for dismissal on the grounds of “impairment of the integrity of the grand jury proceedings’ and the second for the ‘lack of probable cause.’
Prosecutors allege that the infant was a victim of “abusive head trauma” and that Brady had sole care of the baby on Jan. 14, when she was found unresponsive in her crib at her parents’ Cambridge home. She died at a Boston hospital two days later.
Brady was arraigned April 18 in Middlesex Superior Court, where she pleaded not guilty to all charges and was ordered held without bail. She faces deportation to her native Ireland when the criminal case ends because she was living in Boston illegally, federal officials have said.
Prosecutors have said the child was in Brady’s exclusive care at the time she suffered the blunt force injuries that caused her death. Patrick Fitzgerald, an assistant Middlesex district attorney, has said that the child’s injuries were consistent with “violent shaking and direct impact to the head.”
Brady’s defense attorney, Melinda L. Thompson, has repeatedly said that her client did not kill Sabir, and that she has been wrongly accused by Ryan’s office of committing a heinous crime against a child. Thompson could not be reached for comment Wednesday.
Thompson filed the papers last week but also asked that they be impounded because they involve what grand jurors were told during their closed-door proceeding.
The judge has not ruled on the request to impound, but court officials declined to make the paperwork available Wednesday to a Globe reporter.
According to the docket, one motion calls for dismissal of the charges on the grounds of “impairment of the integrity of the grand jury proceedings’’ and the second demands dismissal for the “lack of probable cause.’’
Details of defense allegations are not publicly available.
But the docket sheets cite two well-known Supreme Judicial Court cases, which defense lawyers routinely point to when challenging the ethics of prosecutors before the grand jury or when they believe that there was insufficient evidence heard by grand jurors.
Boston defense attorney Stephen J. Weymouth, who is not involved in the case, said he was surprised by the defense claim that the grand jury did not hear sufficient evidence to charge Brady, given the information about the case prosecutors have already made public.
“It seems like a long shot,’’ he said.
Weymouth said that the attack on the ethics of prosecutors could be more effective, given the long time between when Brady was arrested and when indictments were obtained.
Brady was first arrested Jan. 21, but she was not indicted in the case for until 80 days later.