My thoughts exactly.
As I recall Hotwheels track was orange with white biscuits to join them, and were a devil to fit right up tight, unless you had the strength of Garth of course... which most 9 year olds don't have.
As for you knowing I'd reply with the reference material comment it was all I could think of at the time. Panic, combined with the fight or flight response kicked in. I was just amazed he found out where I kept them. Who'd have thought you kids would look in the cupboard that houses the vacuum cleaner. Got to think of a better hiding place now. Perhaps with the ironing board? ... y'know, that thing I call the folding workbench.
Hide them in the sink, he never does dishes.