Shocking footage caught on a Ring security camera shows a Florida pre-med student hiding a knife behind his back as he walked to his mother's front door before stabbing her "in excess of 70 times."

In the jarring video, 21-year-old Emmanuel Espinoza is seen wearing a pair of dark sunglasses, blue jeans, and a navy blue shirt as he calmly reaches the front door of the home at approximately 2 p.m. Saturday.

Espinoza was headed to a family gathering for his grandfather when Elvia Espinoza, 46, requested her son stay at home with her for the weekend, just two hours south of Orlando.

It's when Espinoza reaches the front door that a concealed weapon can be clearly seen on camera as he clutches it in his left hand, behind his back.

As the pre-med student attempted to enter, his unsuspecting mother opened the door, prompting Espinoza to lunge at her as he stabbed her with the knife at least 70 times.

Polk County Sheriff Grady Judd said Espinoza had been listening to Jay-Z and Kanye West's "No Church in the Wild" as he approached the home, according to the New York Post.

"He knew where to stab her for maximum effect because of his biology classes," Judd explained.

"We have another audio that we're not going to play from the inside of the house, where [his mom is] screaming, 'Manny, Manny, Manny' and he's not saying one word. He stabbed her in excess of 70 times."

"As she tried to get up off of the floor, he stabbed her some more," Judd said.

"He said he noticed her hands were still moving, so he stabbed her some more."

Espinoza called law enforcement soon after and confessed to the crime on scene to dispatchers.

While he allegedly claims he loved his mother, Espinoza was also extremely angry with her and had thought about killing her for years.

He was taken into custody and charged with first-degree murder.