A pre-med student at the University of Florida is in custody after calling 911 on Saturday afternoon and admitting to stabbing his mother to death, the Polk County Sheriff's Office said. 

During a press briefing on Saturday, Polk County Sheriff Grady Judd said that just after 2 p.m., Emmanuel Espinoza, 21, who is a pre-med student at the University of Florida, drove to his mother's house on Saturday afternoon and stabbed her to death.

Sheriff Judd said that Espinonza was driving from Gainesville to Frostproof for a family event for one of his grandparents when the altercation happened. Espinzona asked his mother if he could stay with her and she agreed. 

"He knocked on the front door and when mom opened the door, he began to stab her and he stabbed her many times. She ran from him, she was talking to a family member on the phone and in addition to that, he stabbed her till she fell down and died," Sheriff Judd described. 

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Mugshot of Emmanuel Espinoza over his vehicle

University of Florida med-student admits to fatally stabbing his own mother to death, sheriff says.  (Polk County Sheriff's Office)

Sheriff Judd continued saying that Espinoza admitted everything to them when asked why he did it. 

"He said, "you know, I have wanted to kill my mother for many, many years cause she got on my nerves," Sheriff Judd said, explaining what Espinoza said when asked why he killed his mom. 

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Mugshot of Emmanuel Espinoza, 21

A 21-year-old pre-med student at the University of Florida is in custody after officials with the Polk County Sheriff's Office said he fatally stabbed his own mother Saturday afternoon. (Polk County Sheriff's Office)

Espinoza told deputies that he decided that today was the day he was going to act on his feelings.

"We asked him, 'what's your relationship with your mother?' And he said it was about 8 out of 10 that he really loved her, but she irritated him. And he made up his mind today, on his way from Gainesville, that he would murder her and that's exactly what he did", Sheriff Judd said. 

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Polk County Sheriff Grady Judd talking at the scene of the crime

Polk County Sheriff Grady Judd detailed the horrific murder involving a Florida med-student allegedly stabbing his mother to death.  (Polk County Sheriff's Office)

Sheriff Judd added that Espinoza called 911 following the murder, confessed to the crime, and is now in custody. He is also cooperating with authorities, Sheriff Judd said. 

Sheriff Judd called the murder a "truly horrible event."

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"Elvia Espinoza was 46 years old and a second grade teacher at Ben Hill Griffin Elementary School in Frostproof and is well-loved by the community. It's a very sad day, with an inexplicable, vicious murder. Her family, friends, students and colleagues at the school and with Polk County Public Schools are in our prayers," Sheriff Judd said.

Espinoza was booked into the Polk County Jail and is being charged with first degree murder.