Pre-Med Student Walking to Door with Knife in Hand Before Murdering Mom

A University of Florida pre-med student allegedly stabbed his mom over 70 times with a knife all because he didn't like her – and the moments before the savage murder were captured on video.

Check out this Ring camera footage ... Emmanuel Espinoza was seen casually walking up to the front door of the Polk County home, where his mom, Elvia Espinoza, resided.

Espinoza first tried to open the door, but it was locked, so he knocked on it. Notice the sharp knife gripped in his hand behind his back.

When his mom opened the door, Espinoza barreled inside her house and started stabbing her in a frenzy as she was screaming.

Then Espinoza called 911 and confessed to the brutal crime.

After he was arrested, Espinoza told police he long wanted to kill his mom -- an elementary school teacher -- because he had not liked her for years.

He said he made up his mind Saturday that was going to kill her as he was driving to her home and listening to "No Church in the Wild" by Jay-Z and Kanye West.

He also admitted he knew where to stab her to inflict maximum damage because of his biology class.

Polk County Sheriff Grady Judd held a press conference detailing what happened while playing a clip of the chilling 911 call.