Today in Wisconsin, there is a hearing on the case of a young woman who admits she killed her ex-boyfriend, but claims it was self-defense. She tells a harrowing tale of being attacked and fighting to save her life. Was she really a victim of assault – or was this a cold-blooded murder? "48 Hours" and CBS News correspondent Jamie Yuccas report in "The Case Against Ezra McCandless"

When Ezra McCandless was called to the stand to testify at her own murder trial, no one quite knew what to expect. Some in the media had nicknamed her the "killer girlfriend" while others compared her to infamous convicted murderer Jodi Arias.

McCandless was only 22 when the trial began in October 2019; she was charged with first-degree intentional homicide for stabbing ex-boyfriend Alex Woodworth 16 times in the head, neck, groin and torso.

But before McCandless was questioned about the murder, her defense lawyer asked about her life, wondering why Ezra had changed her name several times. Ezra was born Monica Kay and was later Monica Karlin, but, at her trial, she went by her new self-given name.

Ezra McCandless takes the stand during her trial for the murder ex-boyfriend Alex Woodworth. " She just seemed at times to be enjoying it. There were times on the witness stand where she was smiling or joking," said Jason Mengel, also an ex-boyfriend. Court TV

.As she answered, it became immediately clear to anyone in the courtroom or watching a live stream at home that McCandless appeared extraordinarily relaxed for someone testifying at their own murder trial. She told jurors that Ezra fit her better than Monica and she picked McCandless in honor of free-spirit Chris McCandless, whose life was memorialized in the book and film "Into the Wild."

"I thought it was really interesting when she was asked to spell her name how happy she got, how much she lit up," said childhood friend Julia Post. "When she was spelling it, she was kinda smiling like, 'Yep, this is me. I get to talk about me now.' Like, 'My time to shine.'"

At another point, when McCandless and her defense attorney began talking over one another, Ezra broke out in a laugh.

"When she was on the witness stand, it didn't seem real," said ex-boyfriend Jason Mengel. "She just seemed at times to be enjoying it. There were times on the witness stand where she was smiling or joking."

Watching intently was District Attorney Andrea Nodolf. "Her demeanor during the trial was very relaxed," Nodolf said. "She seemed on breaks excited to see her family. That this was kind of like a family reunion. It wasn't someone who was, 'I'm on trial for first-degree intentional homicide.' This was someone who was wondering when she's goin' home."

Nodolf thought McCandless was emphasizing her femininity to appeal to jurors, especially the first day she testified when she wore a pink sweater. "She was in pink and trying to be very meek and timid," the prosecutor said.

Almost every day of the two-week trial, McCandless came in with different hair styles and items of clothing and it seemed to some that she was drawing attention to herself even when she was not on the stand.

Prosecutors knew that the case boiled down to whether jurors would believe Ezra McCandless was a brave victim fighting off her attacker or a desperate liar playing a master con. Jason Mengel

There was almost electricity in the air when the love of McCandless' life — Jason Mengel, an Army medic — was called to testify. The two had not seen in each other in nearly 18 months.

The moment McCandless heard the words "the state calls Jason Mengel," she began shifting in her seat and looking around the courtroom.

Julia Post says McCandless was wearing her love for Jason on her sleeve. "She just couldn't hide it," Post said. "I think she had went, you know, a year without seeing this person, and there they are. And she wanted attention from him."

Mengel certainly noticed. "On the day I was testifying … I was kinda shocked when I walked in the room," he said. "She's givin' me these looks. Adjusting herself. Like, being overly, you know, attuned to me."

Mengel was asked by a prosecutor to identify McCandless by an item of clothing and he mentioned that she was wearing a pink jacket. She was but, during a break, she took off the jacket to reveal a green sweater underneath. It meant nothing to most court observers, but Mengel knew its significance; he had given Ezra that sweater when she was hospitalized after the attack.

"It was emotional to see the games never stopped," he said. "It was deliberate," Mengel told her. "[Ezra] definitely wore that to get a response outta me."

"It was just shocking," he said. "I don't understand what her tactic was, but I definitely felt uneasy. It just felt like…more of the emotional manipulation I had been put through … I definitely felt like she thought that showing that to me, like, "This is how much I love you still."

McCandless' detractors pointed to the stunned look on Ezra's face when was found guilty and said it was the only true emotion she showed.

After the trial and before she was sentenced, McCandless released a statement blistering her critics and what she called "a prejudicial media:"

"If you breathe, it will be used against you. If you cry too hard or too much, 'she is a fake,'" it read. "If you don't cry enough 'She is Heartless.' If you smile, 'She is not taking this seriously.' If you keep your face calm 'She is unfeeling.' DAILY: Smile, but not too much. It's okay to cry, but not too much. Don't react! But make sure that you show who you are!"

To those who criticized the so-called "family reunions" she had in court during breaks, she wrote that she was acting that way because she had been in jail for so many months unable to see her family. She wrote: "Who would not smile after finally face to face [sic] with family after so long?"

McCandless said she felt "re-traumatized" by the trial and the way she was portrayed as a "sex fiend and a liar." She pointed supporters to her Instagram page, saying she would never stop fighting for her truth and hoped her case would be heard by a higher court.

"The battle for justice," she wrote, "has only begun."