Fans were shocked during the first episode of Investigation Discovery’s Casey Anthony: An American Murder Mystery because after she was arrested on child neglect charges in the disappearance of her two-year-old daughter Caylee, Casey Anthony seemed more concerned about getting in touch with her boyfriend than she was about the whereabouts of her little girl.

But many fans don’t remember that her then-boyfriend, Tony Lazzaro, had a big role in her trial — he took the stand and testified in the murder trial of little Caylee.

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Keep reading to find out more about Tony and how he was involved in the case.

Tony and Casey met on Facebook.

They first met just weeks before the disappearance or death of Caylee, ABC News reported at the time.

Tony spent a lot of time with Caylee and Casey.

He said that during one of the first times he met little Caylee, she came over with a book and a teddy bear, according to his testimony footage. They went down to the pool at his apartment complex. He said that Casey was a good mother and she disciplined Caylee when she got too close to the edge of the pool like "any mother would do.”

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Like any other toddler at that time, Caylee also liked to watch the children’s cartoon Dora the Explorer and she could count to 40 in Spanish, which he said was “incredible for her age.”

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Tony was in college during the time he dated Casey.

Originally from Long Island, Tony attended Full Sail University in Orlando for music and graduated in 2009, according to local paper Riverhead News Review. Casey lived with him at his apartment that he shared with roommates during the 31 days that her daughter was missing.

He said Casey never showed signs that her daughter was missed or dead.

Tony revealed that in the days after her daughter’s disappearance, Casey never appeared upset or sad and she never mentioned anything about it to him.

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He mentioned Casey’s history of abuse from her family.

Tony said that he recalled Casey telling him about physical abuse that she endured from her father, George Anthony, according to ABC News, but she never mentioned sexual abuse.

"Hitting, that's all I can remember…I took it as discipline," Tony said on the stand.

He also said that she briefly mentioned that her brother tried to molest her and “feel her up,” but it was something that stopped immediately.

He kept in close contact with her in the days after Caylee was reported missing.

In a text message obtained by Reuters during the trial, Casey told Tony, "I'm the worst f—ing person in the world.”

She also texted him the day after she reported her daughter missing and wrote, “If they don't find her, guess who gets blamed and spends eternity in jail."