i need help with a book title....?

ok there is a book i read when i was in maybe 4th or 5th grade (around 98-99)

all i remember was on the cover there were clouds in the sky that spelt out the title .... there was a sidewlk with hop scotch on it and a childs shadow ... very colorful vibrant cover.... i wanna say there was a main character name mike hart .... im not sure if that is correct... i remember it being about a little boy who had died.....

i think the title was something like (if i am correct on the name that is ) where is mike hart , what happened to mike hart etc...... something along those lines

it has stuck with me all these years and its killin me that i cant remember it because i want to pick up a copy...

sorry i dont have much info on it.... it was over 10 years ago... if someone has any idea what it could be , please let me know....