Here's what's well established in rodent behavioural science, and what almost nobody in residential pest control ever says to a customer:
Mice navigate and communicate through urinary scent marks.
House mice deposit urine marks continuously as they move. Those marks aren't waste — they're a signalling system. Published work shows mouse urine marks carry information about species, sex, individual identity, social dominance, and reproductive and health status, encoded in proteins within the mark. Mice read the marks other mice leave and adjust their behaviour accordingly.
A mouse running your baseboard at 2am isn't just travelling.
It's writing.
Those marks build a map of your building. Where the food is. Which routes are safe. Which cavity stays warm. Where a dominant animal is holding territory.
And now the part that should make you angry:
When you remove the mouse, the writing stays on the wall.
It doesn't stop when the trap goes off.
It doesn't stop when you seal the entry points.
It doesn't stop when the exterminator's van pulls away.
It stays in the surface of your home, legible to every rodent that comes within range, until something actually removes it.
And here's why wiping down with bleach didn't remove it.
Bleach is a disinfectant a different job entirely. Orkin's own cleanup guidance says so directly: bleach may disinfect but does not neutralize the compounds that cause the odor. Their recommendation is enzyme-based cleaner on every hard surface where urine was present, repeat treatment on porous materials like wood and concrete, and outright replacement of heavily soiled insulation, drywall or carpet padding.
The chemistry behind it: mouse urine is high in uric acid, which doesn't break down easily. It dries into crystals that bond to the surface and reactivate whenever moisture returns.
The mark isn't sitting on top of your baseboard. It's in it.
And pest industry guidance on post-infestation sanitation is blunt about the consequence unsanitized marks stay usable for navigation, and the scent of a previous infestation draws in new rodents looking for somewhere to live.