Casey Anthony is on trial for murder in central Florida, accused of suffocating 2-year-old Caylee with duct tape in the summer of 2008. Her remains were found in the woods in December of that year.
Defense attorneys, who have been trying to paint the Anthony family as dysfunctional, say Caylee drowned in her grandparents' backyard pool and Casey's father, George, disposed of the body.
On Wednesday, lead defense attorney Jose Baez asked George Anthony about his January 2009 suicide attempt. But when prosecutor Jeff Ashton later asked Anthony if he had bought a gun five months before that, Baez objected.
With the jury out of the room, George Anthony said he planned to use the gun to try to get his daughter's friends to tell him what happened to Caylee.
He also said he wrote in his suicide note about "unanswered questions" and that he chose to kill himself because "I needed at that time to go be with Caylee because I knew I failed her."
Ashton argued that the statements were valid for the jury to hear because they rebutted the drowning theory and implied that George Anthony didn't know what really happened to Caylee. Ashton also said the suicide note did not include any reference to George Anthony molesting Casey Anthony when she was a child, as Baez claimed in his opening statement.
Judge Belvin Perry agreed the jury could hear about the gun purchase and the suicide note.
"It looks to me like someone opened the door and someone is trying to walk through it," he said.
When the jury came back, George Anthony got emotional as he recounted the months before his suicide attempt, in which he drove to Daytona Beach and tried to overdose on prescription medication.
He also said he never got the opportunity to confront his daughter's friends because law enforcement confiscated the gun the day after he bought in August 2008. Casey was out on bond and staying in his home, and firearms are prohibited in a place where a person on bond is living.
Karin Moore, a law professor at Florida A&M University, said alluding to the suicide attempt was a misstep by Baez.
"I think it backfired on him," Moore said. "I think his intention was to craft an inference for the jury that George Anthony tried to commit suicide over the alleged abuse and death of Caylee. He opened the door and Ashton correctly pointed it out. "
Moore said she also thinks Baez was trying to avoid putting Casey Anthony on the stand.
"I think (Baez) did nothing but engender sympathy for George Anthony now the jury has contempt for Baez that could certainly reflect on Casey Anthony," Moore said.
Cindy Anthony, Casey's mother, was the first witness called Wednesday. Baez said the defense began the day with about six more witnesses to call, but it wasn't clear if Casey would testify.