A 19-year-old from Boyds was charged Thursday in a fatal, nighttime vehicle collision July 21, Montgomery County Police said in a news release.

Brody Richardson consumed an excessive amount of alcohol and used marijuana before he got behind the wheel of a car that struck the vehicle of Germantown resident Mary Elizabeth Moody, 71, according to detectives.

Moody was trying to turn left from southbound Great Seneca Highway onto eastbound Mateny Road in a white 2018 Subaru. Richardson was driving a black 2021 Mazda northbound on Great Seneca Highway at approximately 94 mph in a 55 mph zone as he approached the intersection, authorities found. Richardson’s car collided with Moody’s, which caused the Subaru to roll over and eject Moody.

Emergency personnel pronounced Moody dead at the scene. Richardson was transported to a hospital with serious injuries.

After a monthslong investigation, authorities found Richardson to be at fault, citing excessive speed and impairment as contributing factors.

Investigators took a blood sample from Richardson at the hospital, and an analysis by the Maryland State Police Forensic Sciences Division revealed a blood alcohol concentration of .2. Maryland law classifies a blood alcohol concentration of .08 or above as driving while under the influence. It was also determined that he used marijuana prior to driving that night, authorities said.

Montgomery Police had a warrant for Richardson’s arrest, and he turned himself in on Tuesday. He was charged with manslaughter by vehicle due to gross negligence and negligent homicide by vehicle while under the influence, among other offenses. He was released on a $10,000 personal bond.