Could very well be honey bees. Could possibly be yellow jackets, or a few "solitary" boring bees (Mason/Carpenter).
Usually yellow jacket colonies aren't large at this time of year, and the solitary bees are very loud individually (sound like little helicopters) but they are few in number and aren't easily confused this the strong low Hummm that is associated with a honey bee colony.
I'm a beekeeper and used to do removals like this for a living. The best course is to pick a mostly sunny day, and between 9am and 6pm, stand back from the house about 20' or so, on the side that you think you heard them, and survey the entire wall and roofline in that area, looking for foragers coming and going. A healthy colony is about 50k bees, and on a sunny day a peak forage hours, you'll see about an average of 1 bee every couple of seconds. 30 bees or so per minute. Focus on gaps in siding, and especially behind gutter fascia, around window frames, flashing around chimneys or exhaust vents, etc.
As far as removal, I would recommend finding a beekeeper with CUTOUT/REMOVAL experience, not just a beekeeper. These jobs are one part beekeeping, and one part construction/remodeling, and there is liability involved.
Regarding the comment above re: Africanized bees... we don't have those at ALL in MO. Their northernmost summertime range is AR/TN, and they die back southward during the winter (due to differences in their gathering/storage behavior vs standard European honey bees).
Teach your kids to hunt and fish and you won't have to hunt for your kids !!