Name this movie in the 80s/90s...? look detail...

The movie starts off with the criminal running away from the police and then jumping into the sea and the police thinking he is dead.
Then a criminal is robbing a jewelry store and robs diamonds and gets away.
The kids dad is a police officer and has all of the pictures of criminals, and the kid believes he see's one criminal on the bus so they find another kid that can pick locks and they break into a flat and stakeout a house across the way.
They bug the mans phone and in the end they find out that the criminal has hidden all of the diamonds in his nieces teddy bears and they become heros.

Comedy, kids movie.
All i can really remember is the fat kid trying to make spaghetti but always failing and the smart kid who has already passed college.