Well it sounds good that your baby is 10 lbs & 3 yrs old & not a wittle kitten.. He is prob. roaming all thru the area down there.. Do leave a water bowl & the tuna so he can get to it.. I was going to suggest some one from SPCA or Humane Society that might know of a way to lure the baby out.. Listen to the area & for steps or meow.. Also smell for your baby to potty & then you can pin point the general area.. Me & the girls send lots of whisker prayers & huggss.. Keep us posted ok..