POLK COUNTY, Fla. — A 21-year-old Frostproof man is in custody after authorities said he drove from Gainesville on Saturday and stabbed his mother to death, claiming that “she got on his nerves.”

According to the Polk County Sheriff’s Office, Emmanuel Espinoza stabbed his mother Elvia Espinoza when she answered the door upon his arrival.

Elvia Espinoza, 46, was a second-grade teacher at Ben Hill Griffin Elementary School in Frostproof.

Espinoza made plans to drive home from the University of Florida Saturday and visit with his mother at her Frostproof home.

Investigators say Espinoza stabbed his mother more than 70 times, attacking her the moment she opened the front door.

“We have another audio from inside the house that we’re not going to show that she’s screaming, Manny! Manny! And he’s not saying one word,” Polk County Sheriff Grady Judd said.

Espinoza, who is facing first-degree murder charges, remains in custody.

Meanwhile, grief counselors will be at Ben Hill Griffin Elementary on Monday.

School district officials said Elvia Espinoza was loved by her students and colleagues, and her death is a devastating loss.

Also, the school has called the parents of the kids in her class.

According to Polk County Sheriff Grady Judd, Emmanuel Espinoza called 911 to confess after stabbing his mother, saying he had wanted to kill her for years because “she got on his nerves.”

“We talked to him and he confessed," Judd said. “‘You know, I have wanted to kill my mother for many, many years because she got on my nerves.” We asked him, ‘What’s your relationship with your mother?' and, he said about an eight out of 10, that he really loved her, but she irritated him.

“This is a horrible event. It's a very sad day with an inexplicable, vicious murder."