Father of the 23-month-old girl who was sexually assaulted and murdered testified on Thursday at the trial of the man accused of carrying out the heinous crime.

Robert Smyth Jr. told jurors how he had to pull his daughter off life support three days after he kissed her goodbye as she went to stay with her mother Amber Bobo, 28. Michael Disporto, 25, the mother’s boyfriend of two weeks, is being tried on charges of first-degree sexual assault and first-degree murder of Ariana Smyth days before her second birthday in July 2016.

Baby Ariana was found to have sustained multiple injuries to her head, arm, back and genitals. Michael has strongly maintained his innocence and claims that the little child injured herself while at the park, according to Daily Mail.

Robert Smyth Jr. and daughter Ariana

(Source: Facebook)

The mother served a sentence of 15 months in prison for failing to seek medical attention for her child. She is set to testify against Michael in order to fulfill the conditions of her plea deal.

According to assistant prosecutor Peter Crawford, Ariana died as a result of blunt force trauma to her head, but also had internal and genital injuries, a broken arm and “head to toe” bruises.

Crawford's opening statements say that Michael, Amber's boyfriend of less than two weeks, offered to take the toddler to the park alone to "get to know her better". Nothing seemed out of the ordinary until Amber woke up in the night and realized that her daughter, who had been asleep in bed with her, was sleeping on the couch, Crawford said.

Robert Smyth Jr. and Ariana. (Source: GoFundMe)

In the morning, she discovered Michael had changed her daughter’s clothes and the girl had bruises on her head, genitals, back, and arm.

According to court documents, though Amber suggested taking her daughter to the hospital, Michael dismissed her. The couple instead went to the mall with little Ariana, where she threw up twice, to which the couple returned home for a while, only to later go back to the mall again with the 2-year-old.

Investigators said that it was when Ariana threw up for the third time and her eyes rolled back into her head that Amber showed cause for concern and decided to call 911. Michael again dismissed Amber, saying that the little girl was just tired and that he'd leave Amber if she proceeded to follow that course of action.

Amber finally decided to call 911 at 6 pm and Ariana was rushed to the hospital where she required brain surgery. She also had a fractured arm, pulmonary contusions, and genital injuries.

Robert, the girl's father, on Thursday recounted the time he was summoned to the hospital three days after last seeing his daughter only to find her in a comatose state caused by repeated blows to the head. He told the court that he had to pull his daughter off life support.

Though Disporto's defense attorney told the jurors that the police have no DNA evidence proving that his client raped the toddler, the prosecution argued that Disporto is the only person who could have assaulted and killed Ariana.

The trial continues.