SUPPOSED TO BE A DAY TO CELEBRATENovember 15th was supposed to be a day for Jennifer to celebrate. She spent most of the day before preparing for her 2-year-old daughter's birthday party.Receipts found in her abandoned car show she ordered a Dora Explorer cake for her daughter and went to Party City where she bought a party supplies and a pinata.It was a party she wouldn't miss for the world, so when she didn't show up, her family knew something was wrong.The court documents show her family and friends made several attempts to call her, but she never picked up. They filed a missing persons report.They suspected Brown had something to do with her disappearance.Their suspicious were only heightened when they called his cell phone.This is the voice message they heard quot;I'm not answering the phone because I am going to be gone. I did what I had to do and now it's done. You probably won't see me again. Just don't forget me.quot;Brown turned himself in after learning he had an outstanding warrant for violation of probation.ALLEGED CONFESSIONThe documents also tell us about an alleged confession to a fellow inmate the county jail.An inmate who shared a lockdown unit with Brown told detectivesBrown showedhim how he choked Johnson and when she fell unconscious, he threw her in the trunk.The inmate said Brown then told him quot;he had to get rid of herquot; because he quot;knew she would put him in jail for a long time after what he did to herquot;.The documents say Brown told the inmate he saw police around while Jennifer was in the trunk. Not long after that, he found out she had made the 911 call. He allegedly told the inmate, quot;It was the last mistake she ever made with him.quot;The inmate said Brown also expressed concern about DNA evidence, worried about the quot;like CSI stuffquot;.In a disturbing recollection, the inmate said Brown told him quot;It weird, if felt good to choke that (explicative), like it gave him eternal life. He also said, quot;He cannot explain the feeling you get when you kill people.quot;The last statement in the interview with the inmate, he told detectives Brown said quot;even if he could, he would not change things.quot;THe hundreds of pages document several incidents of violence committed by Brown against Johnson, including during her pregnancy with their daughter.In most cases though, she asked to drop the charges.The two were seen arguing at a Tampa night club before she went missing.Prosecutors filed to seek the death penalty last month. EARLIER STORYTAMPA, Florida --Prosecutors have released a copy of the chilling 911 call a Tampa mother made from inside the trunk of a car before authorities say she was murdered by her ex-boyfriend.In the call, 31-year-old Jennifer Johnson frantically tells an operator she is inside of her car trunk as loud music plays in the background. The operator asks where she is at. Johnson says she doesn't know.The call ends abruptly about a minute later.JOHNSON -- Ma'am, I'm in the trunk right now. (Inaudible) took my car. They got me in my car... I don't know where I'm at.911 OPERATOR -- Where are you?JOHNSON -- I don't know, I'm in the trunk of my car. I'm in my car right now. (Inaudible) I don't see anything, I'm inside of a trunk. They took my car and I'm inside of a trunk.911 OPERATOR -- OK, stop screaming, because I can't understand you.JOHNSON -- OK... They turned the music down.911 OPERATOR -- Are you in the trunk of a vehicle?JOHNSON -- Yes.911 OPERATOR -- Where did they pick you up at?JOHNSON -- I don't know where I'm at.911 OPERATOR -- Where did you start out at?JOHNSON -- (Inaudible)911 OPERATOR -- Did you start somewhere in Plant City? (Disconnect)Johnson's family reported her missing after she failed to show up at the birthday party she planned for her 2-year-old daughter. She was found dead in an abandoned home in November.Her ex-boyfriend, George Vincent Brown, has been charged with her murder. Also released was audio of Brown's voice mail, where he said the following:quot;I'm not answering the phone, because I am going to be gone. I did what I had to do, and now it's done. You probably won't see me again, just don't forget about me.quot;/>