"They were walking on dead bodies and we actually saw a man who was holding his daughter in his hand," said Dorreal Fluker. "She just died in his hand. It made me feel bad and I started crying. I started to worry about my little sisters and brothers."
"How does a young person process that kind of stuff - seeing things like that?" asked CBS News correspondent Byron Pitts.
"At the time, I didn't want to process it," Dorreal said.
But for these New Orleans high school students, the lingering scar of Hurricane Katrina isn't what happened four years ago, it's what hasn't happened four years later.
"I lived in the Ninth Ward," said Victor Carter, a senior at the New Orleans Charter Science and Math High School. "I have to go to school and I travel seven miles every day and see that the Ninth Ward is still the same."
In fact, just 2,600 of the 14,000 residents who lived in the lower Ninth Ward before Katrina have returned. While much of New Orleans is getting back to normal, the areas hardest hit still struggle - especially the children.
"It makes me mad sometimes," Victor said.
Experts say getting over mental trauma from disasters like Hurricane Katrina normally takes about three years. But as New Orleans closes in on a fourth anniversary, health officials believe it could take adults and children here three times longer to heal from their psychological wounds.
"Our young people here in New Orleans were forced to face a very adult situation," said Dr. Jullette Saussy, the superintendent of the New Orleans Emergency Medical Services. "And it had some consequences."
Four years ago, CBS News first met Saussy outside the city's convention center. She and her team ankle deep in water and chest deep in a healthcare system that was overwhelmed and broken. Today, she says, it's the mental health system that's busted. And children here are paying for it.
"A lot experimented with substance abuse, a lot of self medication, a lot of drinking, a lot of drugs," Saussy said.
According to a 2007 study, it's estimated that there are 45,000 children in the city that have some kind of mental health problem. This year alone, there have been 40 suicides among adults and children - the youngest person was 11 years old.
"Anybody that knows anything about children knows that the best-case scenario is to have children in a supportive environment for any kind of treatment," Saussy said.
CBS News first met an emotional Tyronne Smith, then 13, seven days after he was forced to evacuated to Baton Rouge.
"I lost my house, my dogs," Smith said. "It has just been horrible."
Now a junior in high school, Tyronne credits his parents and counseling for helping him to move on.
"Katrina changed everything in an instant," Tyronne said.
"That is a tough lesson for a kid to learn?" Pitts asked.
"Yep, I've learned it, so now I value everything," Tyronne said.
Earlier this year, the Smiths moved back to their home which was once under five feet of water.
Tyronne said life is great for him now.
"I am back with my family, back with my friends," he said. "I made new friends."
Back home in a city that is slowly putting the pieces back together.