(CNN) -- Casey Anthony's defense attorneys pushed Monday to have statements made by their client to law enforcement and relatives thrown out ahead of her murder trial, claiming the Florida single mother wasn't read her Miranda rights until three months after her daughter Caylee was reported missing.
The defense and prosecutions offered final arguments Monday in a hearing on these questions, which could prove critical once the trial starts in May. Anthony, now 24, faces seven charges related to the death of her 2-year-old daughter -- first-degree murder, aggravated child abuse, aggravated manslaughter of a child and four counts of lying to law enforcement.
Her defense lawyers argued Monday that Anthony thought she was in custody in July 2008 when she first talked to police, before she'd had her constitutional rights as a criminal suspect read to her.
"She was handcuffed, patted down, placed in a car, which is a cage, (and she) could not get out," attorney Cheney Mason said.
But Assistant State Attorney Linda Drane Burdick countered that the suspect words should not be off limits, claiming she freely and voluntarily spoke with police and had not been detained. Early in the investigation, police were looking at a woman named Zenaida Gonzalez -- whom Anthony said was the girl's babysitter, a claim the woman later denied -- and not Anthony as the prime suspect in the girl's disappearance, according to the prosecution.
"In no way did Ms. Anthony, or would a reasonable person, believe that they were in custody during any point in time when she was giving statements to the Orange County sheriff's office," Burdick said Monday. "Not being subject to custodial interrogation, Ms. Anthony was not entitled to her Miranda rights."
Caylee Anthony was last seen alive June 16, 2008, by her grandfather George Anthony. Authorities began looking for her just under a month later, after Cindy Anthony called police to report her granddaughter was missing and also to accuse her daughter Casey of stealing her car and money.
Casey Anthony ended up in jail on July 16, the day after the investigation opened, and faced charges of child neglect and for providing false information to police before eventually being charged with murder. Months later, on December 11, 2008, Caylee's decaying body was discovered on the edge of the family's neighborhood about 10 miles southeast of downtown Orlando.
Another key issue in the pre-trial hearing that finished Monday is whether statements that Casey Anthony made to George, Cindy and Lee Anthony -- her parents and brother, respectively -- can be entered into evidence at the upcoming trial.
The defense has argued that these three acted effectively as "agents of the state," as law enforcement officers repeatedly encouraged them to talk to Anthony while she was in jail. But the prosecution claims that the family and authorities were simply trying to get answers about the whereabouts of young Caylee.
"I wanted any and every asset -- any capable body -- to assist in finding my granddaughter," George Anthony testified last week. "And if that meant somebody going in there and improperly talking to my daughter ... legally or illegally, I was willing to do that."
His wife, Cindy, admitted that she spoke frequently with law enforcement while her daughter was considered a suspect. But she claims she did not "knowingly or willingly" help build a case against Casey Anthony.
During a videotaped jailhouse conversation shortly after his sister's arrest, Lee Anthony promised Casey he'd keep secret any message she sent him. When asked last week if he was lying about that promise, the suspect's brother said "maybe" -- while adding that, like his parents, his main goal was to find his niece Caylee.
Chief Judge Belvin Perry, of Florida's 9th judicial circuit, is expected to rule next week on whether certain of Casey Anthony's statements to law enforcement and relatives can be used in the upcoming trial.