Orlando, Florida (CNN) -- The brother of Florida child murder suspect Casey Anthony acknowledged Thursday that he tried to coax information out of his sister during jailhouse visits, but denied police put him up to it.
During a videotaped jailhouse conversation shortly after his sister's arrest, Lee Anthony promised to keep secret any letter she sent him while she was being held in connection with the disappearance of her 2-year-old daughter Caylee.
"(Did) you tell your sister that if she gives you a letter through this letter system, that you won't share it with anyone if she doesn't want you to?" defense attorney Jose Baez asked Lee Anthony during the pretrial hearing Thursday. "And say that to her from brother to sister?" Lee Anthony told Baez he had.
"Were you lying?" Baez asked.
"Maybe," Anthony said, as his sister looked away with a shrug. But Anthony said he was only trying to help find Caylee, whose body was found five months after her reported disappearance, and that police never forced him to do anything.
Casey Anthony is charged with capital murder in the girl's death. Defense lawyers are asking a judge to throw out all statements she made to police, arguing that police failed to read her her rights when she was first arrested and that investigators tried to coax statements out of her through her relatives.
Her brother, father and mother have all testified during the latest two days of pretrial hearings, with her father alternately tearing up and sparring with prosecutors during Thursday's session.
"I don't know why you're going in this direction, because right now, I wish you could change places with me," George Anthony, Casey's father, told prosecutor Linda Drane Burdick at one point. When Burdick objected to being challenged by the witness, he shot back, "I will challenge you."
When Circuit Judge Belvin Perry told George Anthony to stick to answering questions, George Anthony replied, "This is a very emotional time, sir." Asked if he needed a recess, he said, "I'm fine. I just want to get this over with."
Wednesday, Orange County Deputy Sheriff Ryan Eberlin said he handcuffed Anthony after he arrived at her parents' home following three 911 calls from the defendant's mother, Cindy Anthony. Cindy Anthony has said she called police to accuse her daughter of theft after learning her granddaughter had been missing for a month, hoping to get her daughter thrown in jail in hopes of finding out what happened.
Prosecutors argue that all questioning was voluntary and that Anthony was free to leave if she wanted. Eberlin testified Anthony was only cuffed for about four to five minutes, when a supervisor told him to release her. Sheriff's Cpl. Yuri Melich said he had "no reason" to read Anthony her rights, because "she was the mother of a missing child."
"She wasn't being interrogated as a suspect of a crime," Melich said. "We were still investigating where her daughter was."
In Session's Jean Casarez and Nancy Leung contributed to this report.