Hundreds of people spent part of their Monday evening at the William Paca Elementary School – to remember 8-year-old Troy Douglas.

The boy was walking home from school last week when witnesses said a home exploded – and a brick wall collapsed on him.

At the vigil the choir from William Paca fought through tears to sing Katy Perry's song "Roar," and teachers shared their memories of Troy Douglas.

"I will miss calling his name and his just looking at me. I'll never forget his beautiful smile," said teacher Alena Koshansky.

They also talked about his sense of humor – like the time he forgot his homework.

"Troy decided that he was going to go with the good old, 'The dog ate my homework' and the class erupted in laughter," said teacher Shanae Snowden. "I just stared at him. I wanted to laugh so badly."

They also said Troy was a strong writer.

"You just got this sense when you read Troy's work that he was a kid who just loved being a kid," said teacher Joshua Rothschild. He said he saw Troy Douglas on the playground, just before he started that last walk home.

"That day he came right over to me and he gave me a high five," Rothschild said. "And I got to say goodbye to Troy that day. And I didn't know what that goodbye meant at the time, but I do now."

Investigators have not said what caused the fire and building collapse at that home; they've still not confirmed there was an explosion.