Alyssa Bustamante has been sentenced to life in prison for the brutal murder of her nine-year-old neighbor, Elizabeth Olten.

Bustamante, 18, was described as a remorse-less thrill killer by prosecutors.

Excerpts from her diary, which describe her excitement after the murder, were used during her trial to help prosecutors push for a longer prison sentence.

I strangled them and slit their throat and stabbed them now they're dead,'' Bustamante wrote in her journal.

''I don't know how to feel atm. It was ahmazing. As soon as you get over the 'ohmygawd I can't do this' feeling, it's pretty enjoyable. I'm kinda nervous and shaky though right now. Kay, I gotta go to church now...lol.

Below is a comprehensive timeline of nine-year-old Elizabeth Olten's murder and the trail of teen killer Alyssa Bustamante, who has since expressed remorse.

She's an evil monster, Olten's mother Patty Preiss said at the sentencing hearing. I hate her.

Timeline of Elizabeth Olten Murder Case:

Jan. 28, 1994: Alyssa Bustamante is born to a broken family: her mother abandoned her when she was younger, and her father is still in prison for an undisclosed crime.

2007- October 2009: Bustamante overdoses on painkillers and begins to self-mutilate, carving the word hate into her arm. She is diagnosed with severe depression and put on antidepressants. She changes her list of hobbies in an online profile to include killing people and cutting.

Oct. 16, 2009: Alyssa Bustamante digs two graves a week before Elizabeth Olten is murdered. Police have not released any information on who was meant for the second grave.

Oct. 21, 2009: Olten goes missing around 6:15 p.m. after supposedly walking home from a friend's house. Bustamante lures Olten to the woods by asking her younger sister to invite Olten over to play.

Oct. 21, 2009: Alyssa Bustamante stabs Elizabeth Olten, strangles her to death and cuts her throat. She wanted to know what it felt like [to kill someone], Missouri State Highway Patrol Sgt. David Rice would later testify.

Oct. 22, 2009: FBI is called in to help with search for Elizabeth Olten. Volunteers concentrate on location of cell phone's last signal, in the woods behind Olten's home.

Oct. 23, 2009: Searchers find the body of nine-year-old Elizabeth Olten.

Oct. 24, 2009: Alyssa Bustamante, 15, is charged with first-degree murder.

Oct. 28, 2009: Elizabeth Olten laid to rest in pink casket. The nine-year-old's body is carried by a horse-drawn carriage to the cemetery.

Nov. 18, 2009: Alyssa Bustamante is certified as an adult and indicted. Defense attorney Kurt Valentine pleads with judge to leave the case to the juvenile court, arguing that federal prison would be a death sentence for his client. Judge Beetem rejects the argument.

March 5, 2010: Lawyers on Alyssa Bustamante case agree to hold trial in Jefferson County, Mo., but to choose jury from Greene County, Mo.

May 11, 2010 - August 28, 2010: Bustamante denied the right to continue her high school education behind bars. Bustamante's attorney Charles Moreland protests Judge Joyce's ruling. As such, she's protected by Missouri law and the Missouri constitution that gives her the rights to an education.

August 30, 2010: Prosecutors request the knife allegedly used in Olten's murder and Bustamante's clothes for DNA testing. The test consumes the full sample, leaving nothing for the defense to test independently.

Oct. 16, 2010: Bustamante's lawyers take the question of her continued education to the Missouri Supreme Court. The case is rejected on a technicality.

Oct. 21, 2010: One year memorial service held for murder victim Elizabeth Olten.

March 11, 2011: Alyssa Bustamante's defense team prepares for her murder trial. The teenager continues to plead not guilty to the charges against her.

June 22, 2011: Cole County Circuit Judge Patricia Joyce rules that at least part of Bustamante's statement to police, which prosecutors have treated as a confession, is not admissible, ruling that the officers questioning the teenager used deceptive tactics. Unspecified passages from police transcripts are barred from use by the prosecution.

August 23, 2011: Alyssa Bustamante trial delayed for third time. Her new trial is set for early 2012.

Jan. 9, 2012: Alyssa Bustamante withdraws not guilty plea for first degree murder.

Jan. 10, 2012: Bustamante pleads guilty to second degree murder and armed criminal action in exchange for giving up her right to a jury trial.

Jan. 10, 2012: Judge Joyce asks Bustamante if she was aware of her actions and their consequences when she murdered nine-year-old Elizabeth Olten. Yes, Bustamante replied.

Feb. 7, 2012: Closing arguments are made in the sentencing hearing for Alyssa Bustamante. Alyssa should get out of jail the same day Elizabeth gets out of the grave, Olten grandmother yells from her wheelchair. Bustamante's grandmother exits the court, crying.

Feb. 8, 2012: Alyssa Bustamante is sentenced to life in prison for second degree murder and thirty years for armed criminal action, the sentences to be served consecutively. She was not denied the possibility of parole.

Feb. 8, 2012: Bustamante speaks to the Olten family, expressing remorse for the murder of Elizabeth Olten. If I could give my life to get her back I would, she says. I'm sorry.

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