A child whose throat was cut and who allegedly witnessed the killing of her mother and brother at a BREC park near Zachary in 2008 is at the center of a legal fight being waged in two Baton Rouge courts.

The East Baton Rouge Parish District Attorney’s Office has indicated it wants jurors in the upcoming capital murder trial of Trendall Lashel Matthews to hear from first-responding sheriff’s detectives and medical personnel what the girl — who was 4 at the time of the incident — told them.

Prosecutors have not ruled out the possibility of putting the girl on the witness stand.

Dominique Dantoni Smith, the girl’s father and Matthews’ boyfriend, also is charged with two counts of first-degree murder and two counts of attempted first-degree murder. They will be tried separately.

Matthews’ trial is scheduled to begin July 25.

Matthews’ attorneys asked the state 1st Circuit Court of Appeal on Monday to review state District Judge Tony Marabella’s denial of their motion to determine before trial whether a 4-year-old witness has the capacity to accurately recall traumatic events.

Matthews’ attorneys also are challenging Marabella’s denial of their request to appoint a psychologist to evaluate the child’s capacity to testify.

“This child saw her mother slashed to death, her brother slashed to death and had her own throat cut. She remained in the woods with her dead mother and brother, and her 6-month-old sister — who was untouched — for nearly 24 hours,’’ Matthews’ appellate attorney, Mark Plaisance, wrote to the 1st Circuit.

“She claimed her father and a woman not only killed her mother in a most heinous manner, but watched as they burned the bodies of her mother and brother. She was not found until the next afternoon, at which time she was diagnosed with medical shock, dehydration and mosquito bites,’’ Plaisance added.

Plaisance said the child “may desire to tell the truth but may lack the ability — given the horrific trauma — to distinguish the actual events from how she then perceived, and now recalls, these events.’’

Marabella said last month he will decide at trial whether the child has the competency to testify.

If the child is not called to testify at trial, and in the event her out-of-court statements are found to be admissible, the child will not undergo a competency evaluation or hearing, the judge ruled.

Marabella also said he will not appoint a psychologist to interview the child, and will not allow expert testimony at trial regarding a minor child’s capacity and the effects on a child’s perception after a traumatic event.

The judge is scheduled to rule next week on the admissibility of the girl’s statements to first responders.

Assistant Public Defender Scott Collier, one of Matthews’ attorneys, filed a memorandum in the 19th Judicial District Court Monday opposing the use of the child’s statements.

Collier argues that law enforcement’s efforts to gain information from the girl “cannot trump the right to confront and cross-examine accusers.’’

Fellow Assistant Public Defender Fred Kroenke, who also represents Matthews, filed another memorandum in the 19th JDC in support of the defense’s request to call an eyewitness identification expert at her trial.

“The thought of the incredible injustice of wrongful conviction or, worse yet, wrongful execution ought to be enough incentive for our judicial officers, prosecutors included, to welcome expert guidance to avoid any such possibility,’’ Kroenke wrote.

Prosecutor Darwin Miller called the defense motion “an attempt to attack a potential witness’ ability to identify an assailant.’’

“The Louisiana Supreme Court has specifically held such testimony to be improper,’’ Miller wrote, citing the high court’s ruling last year in a capital murder case involving a killing outside the Olive Garden restaurant on Siegen Lane in 2006.

Prosecutors are seeking the death penalty against Matthews, 25, of Jackson, and Smith, 30, of Wilson, in the May 4, 2008, deaths of Smith’s former girlfriend — Jessica Johnson Palmer — and her 3-year-old son, Juan Palmer Jr.

Matthews and Smith also are charged in the attempted first-degree murder of Lindsay Paige Johnson — the child at the center of the ongoing legal battle — and her younger sister, Robbyn Palmer, who was not injured but was also left for dead at Doyle’s Bayou Park on Pride-Port Hudson Road.

Lindsay Johnson and Robbyn Palmer are two of Jessica Palmer’s children.