DOUGLASVILLE – The Douglas County teenager charged with killing his great-grandmother with a Samurai sword will undergo a mental evaluation after being charged as an adult.

WSB’s Richard Sangster was in the courtroom Wednesday as the judge read the charges against 15-year-old Gevin Allen Prince. Prince said he understood the charges of malice murder and aggravated assault.

District Attorney David McDade says the charges stem from attacks on Prince's great-grandmother, 77-year-old Mary Joan Gibbs, who was killed, and on his grandmother, 55-year-old Laura Prince, who is recovering from her wounds.

McDade says he has no choice but to charge the teen as an adult.

“He’s charged as an adult because the Georgia Legislature has made it clear someone 15 years of age who commits this crime is charged as an adult,” McDade said. “He’s charged with a very brutal set of crimes and we’ll start the process of having him evaluated and if he has mental health issues, those will be taken into consideration.”

The assault charges were filed because Prince, with his sword, chased two neighbors who tried to stop the attack. The neighbors, both juveniles, were not hurt, said McDade.

Police say they arrived at the home in the 3400 block of Spring Ridge Drive in Douglasville to find Gibbs dead in the yard. Gevin Prince was standing in the doorway with the sword and a pellet rifle. He shot the windows out of a patrol car with that rifle.

After a 10- to 15-minute standoff, the suspect was talked out of the house and into the yard, where police used a Taser and K-9 dog to subdue him.

Sheriff Phil Miller said the teen was arrested in June on a similar incident in which he was wielding a different sword.  He got into trouble again in July.  Both times he was sent to a mental institution but was eventually released.

Prince is being held at the Douglas County Jail without bond.