A 15 14-year-old boy was charged Wednesday with second- and third-degree assault in connection with the attack on a Metro bus driver early Saturday morning in Tukwila.

"Any assault on a bus driver is a very serious matter," said King County Prosecutor Dan Satterberg. "In addition to the harm to the bus driver, the passengers, other motorists and pedestrians are all put at risk when a driver is attacked."

Based on the victim's injuries, second-degree assault is the maximum charge, according to a news release from the Prosecutor's Office. Because state law sets strict parameters for allowing adult prosecution, the 15 14-year-old defendant is not eligible for adult prosecution because of his age, lack of criminal history and other factors. However, King County Prosecutors will request a sentence above the standard range on the assault charge based on the seriousness of the offense and the risk to community safety.

Under state law, the standard sentence range in Juvenile Court for assault in the second degree is 15 to 36 weeks in detention, but prosecutors will recommend a sentence of over a year of incarceration if the defendant is convicted, according to the news release.

Two other boys, ages 16 and 17, were charged with first-degree malicious mischief for breaking windows on the back door of the bus and damaging the door frame. Their cases are also required to remain in Juvenile Court where they each face a maximum sentence of up to 30 days in detention, the news release says.

Two of the defendants remain in custody. The 16-year-old charged with malicious mischief is currently out of custody on electronic home-monitoring. All three are scheduled for arraignment on Jan. 28 at 9 a.m. in Juvenile Court.