WASHINGTON (CNN) -- Eleven-year-old Carl Joseph Walker-Hoover liked football, basketball and playing video games with his little brother. 

Rep. Carolyn McCarthy says the effects of bullying are becoming more severe. 

But on April 6, after enduring what his mother called "relentless" bullying at school, Carl hanged himself with an extension cord in the family's Springfield, Massachusetts, home. 

"What could make a child his age despair so much that he would take his own life? That question haunts me to this day, and I will probably never know the answer," Sirdeaner Walker said in a House Education and Labor Committee hearing on school bullying. 

"He had just started secondary school in September, and we had high hopes," she said. "But I knew something was wrong, almost from the start." Watch Sirdeaner Walker describe finding her son's body » 

He didn't want to say at first, she said, but reluctantly told her of classmates who called him names, "saying he acted gay and calling him faggot," Walker said. 

"Hearing that, my heart just broke," she said. 

Rep. Carolyn McCarthy, D-New York, said the emotional and physical effects of bullying are becoming more severe and that the acts of bullying can continue outside school. 

According to the National Youth Violence Prevention Resource Center, about 30 percent of school-aged children in the United States are estimated to be involved in bullying, as either a bully or the target of a bully. 

Steve Riach, the founder of Heart of a Champion Foundation -- a nonprofit organization that says it offers educators an "innovative and effective approach to developing character in the lives of their students" -- said his organization has learned that students recognize that school safety cannot be accomplished only with security guards and metal detectors. 
How many school kids are part of bullying in the U.S.?
What role can a kid play?
Who put that number out?
Who started the Heart of a Champion Foundation?
What two things does he say is not enough to make schools safe?
How old was Carl Joseph Walker-Hoover?
What did he begin in the fall?
Did it go well?
What did kids in his class do
like what?
What happened on April 6th?
With what?
Where?
Where did he live?
Did he have siblings?
Which sex?
did he like sports?
Which ones?
Did he have a hobby?
What is his mom's name?
about 30 percent
 about 30 percent of school-aged children in the United States are estimated to be involved in bullying
a bully or the target
as either a bully or the target of a bully
National Youth Violence Prevention Resource Center
According to the National Youth Violence Prevention Resource Center
Steve Riach
Steve Riach, the founder of Heart of a Champion Foundation
security guards and metal detectors
his organization has learned that students recognize that school safety cannot be accomplished only with security guards and metal detectors
eleven
 Eleven-year-old Carl Joseph Walker-Hoover
secondary school
He had just started secondary school in September
no
But I knew something was wrong, almost from the star
called him names
 classmates who called him names
faggot
saying he acted gay and calling him faggot,
he hanged himself
on April 6, after enduring what his mother called "relentless" bullying at school, Carl hanged himself with an extension cord 
an extension cord
 Carl hanged himself with an extension cord
at home
 in the family's Springfield, Massachusetts, home
Springfield, Massachusetts
n the family's Springfield, Massachusetts, home
yes
his little brother
male
his little brother
yes
Eleven-year-old Carl Joseph Walker-Hoover liked football, basketball 
football and basketball
 liked football, basketball 
playing video games
playing video games with his little brother
Sirdeaner Walker
Sirdeaner Walker describe finding her son'