18-year-old Cody Hall of Pleasanton, California struck and killed 58-year-old Diana Hersevoort as she was biking with her husband on June 9th. Hall's initial charge of vehicular manslaughter has been upgraded to second degree murder after prosecutors discovered he enjoyed bragging about his speeding habits on Twitter.

In order to prove second-degree murder, prosecutors need to show that a driver had an intentional disregard for human life. It happens often with repeated drunk drivers whose disregard for DUI laws eventually ends in a death. In this case Hall's pattern of bad behavior wasn't only documented in his driving record, but in his tweets:

An analysis of Hall's driving record and pattern - along with Twitter posts in which he talked about how fast he liked to drive - factored into upgrading the case to murder, authorities said.

Hall had just graduated from Foothill High School in the days before the incident and parents at the school confirmed to the Pleasant Hill Patch that he often posted messages referring to his car as the "death trap" and photos of his speedometer at high speeds.

According to police, Hall was doing 83 miles per hour in a 40 mph zone. He was passing another vehicle when he lost control of his 2004 Dodge Neon and collided with the couple in the bike lane on Foothill Road. Diana Hersevoort was killed and her husband 57-year-old Johannes Hersevoort was severely injured in the incident. Hall has also been charged with reckless driving.

Hall's father, 43-year-old Aaron Hall, has two felony convictions and was also arrested when authorities found two llegal assault rifles in the home during a search related to his son's case.

[Chron]

[Pleasanton Patch]

[Pleasanton Weekly]

[Mercury News]