When this type of thing happens in a pharmacy you should report it to the State licensing bureau. They will investigate errors and esp Controls like this.

It is best to take a photo of the error bottle, or at least keep it,
for evidence.

This experience of yours is fairly extreme and uncommon. Something should be done. The police can only enforce criminal laws. They don't really have juristiction over professional behaviors unless you die, or are approached outside for illegal sale etc. I would contact Walgreen's customer service, completely bypass the store managers etc, and report this behavior, so Walgreen's can put in their cameras, or turn them on etc. Most big chains have secret security that can tape employees on the counter. Then they have evidence to proceed.
If you threaten the employees, pharmacist or manager, they will stop their stealing and be harder to catch. By going around them, you can set a wheel in motion to fix the problem a different way.

Be organized in your complaint, have photos of the bottles, initials of the pharmacist, dates, times etc, so they can go back on the schedules to see who was working at which time.