Driver Arrested in Death of Boy With Autism Who Was Left on Bus For Entire School Day

Hun Joon Lee, 19, a nonverbal student with autism and the mental capacity of a three year old, was left on a school bus for an entire day.

A California school bus driver was arrested in connection with the death of a special needs student who was left unattended for an entire day on a parked school bus, officials said.

Hun Joon Lee, 19, had been picked up in September at 8 a.m. by a bus to attend Sierra Adult School, Whittier Police said.

Lee's family said he had autism and was nonverbal with the mental capacity of a three year old. His mother called the school to say he never returned home from school that day, and she was told the boy had never arrived.

Police responding to a 911 call from the bus yard on Greenleaf Avenue found drivers attempting to resuscitate Lee, according to reports.

Cops also tried to revive the teen, but he could not be saved. He was pronounced dead at 4:33 p.m., about 10 minutes after police arrived, officials said.

Read: Teen with Special Needs Hitchhiked Twice After Being Left on School Bus

There were reportedly no signs of trauma on Lee’s body, which family said was found in the aisle of the bus. No weapons were found at the scene.

More than six months after Lee’s death, bus driver Armando Able Ramirez, 37, Ramirez was taken into custody at his Apple Valley home, police said Wednesday.

He was charged with dependent abuse and his bail was set at $50,000, officials said.

On the day Lee was found, Ramirez was questioned by investigators and released.

Lee’s family was devastated by his death and questioned how the teen, known by many as “Paul,” could have been overlooked on a bus that was driving only three other students that morning, KTLA reported.

“My boy is a very, very precious boy,” his mother, Eun Ha Lee, told the news station. “I don’t know other people, how they think about my son, but my son is perfect to me.”

Lee had attended Sierra Adult School’s transition program, an extended adult learning setting that serves 18- to 22-year old special needs students, Sandra Thorstenson, Superintendent of Whittier Union High School District, said in a statement after his death.

Read: Family of Kentucky Couple Missing in Brussels Were Mistakenly Told They'd Been Found

He was described by loved ones at a prayer vigil as a gentle young man who smiled a lot and who enjoyed people, Christian music and the movie ‘Toy Story,’ she said.

“Paul’s death has been devastating to our entire education community. For weeks, we have cried, held each other, and prayed for Paul and his family,” Thorstenson said.

“We remember the fun Paul had washing cars and getting wet during his work training. I was reminded how his Elvis impersonation stole the show in his high school lip sync competition.

“In all the stories and anecdotes, we remember the joy Paul brought to us that reminds us why we dedicate our lives to the profession of education.”

Lee’s death inspired legislation pending in California to improve school bus safety.

Introduced by Senator Tony Mendoza, SB 1072 is meant to “prevent future tragedies by requiring every school bus in the state to be equipped with a child-safety alarm system,” he said.

“No parent should fear that their child will not return home safely at the end of the day,” Mendoza said in a statement.

Ramirez is expected to be arraigned on Friday.

Watch: 5-Year-Old Girl Saves Mom from Drowning After Having Seizure in Pool