Over a dozen people were recently arrested for selling marijuana to undercover detectives. Many 9NEWS viewers were - at the very least - confused as to why Denver Police raided eight Sweet Leaf locations and made several arrests.

Allow us to help you weed through the facts on this convoluted story.

The rules for marijuana shops ban them from selling more than one ounce per transaction. Not more than one ounce per day.

RELATED | PD: Budtender sold ounce of pot to undercover cop 9 times in 2 hours

So, how, then, are police justified in arresting these budtenders?

Because there are rules for pot sales and there are laws.

The state's marijuana rules say that pot shops can't sell you more than an ounce per transaction:

Rule 402 C-3 – Colorado Dept. of Revenue:
A Retail Marijuana Store and its employees are prohibited from selling more than one ounce of Retail Marijuana flower or its equivalent in Retail Marijuana Concentrate or Retail Marijuana Product during a sales transaction to a consumer.

Clear and concise.

But then, going up to Colorado's highest law - the state's constitution - and you'll find it only allows:

Possessing, using, displaying, purchasing, or transporting... one ounce or less of marijuana.

Having more than an ounce, then, according to the Colorado Constitution, can be a crime.

The state statutes - that is, laws passed by the legislature - punish you with fines and jail time if you possess or sell more than an ounce.

Pro-marijuana advocacy group NORML has a handy guide to the criminal punishments for possession and sale. Read through that information at this link.

And here are the laws listed on the warrants that Denver Police used to go after these pot shops.

Those laws, by the way, don't care how many transactions it takes to add up to more than an ounce. All the same: the state rules will change on New Year's Day to make it clearer.

The new language in Rule 402 (that's not a typo) can be read below:

A Retail Marijuana Store and its employees are prohibited from Transferring more than one ounce of Retail Marijuana flower or its equivalent in Retail Marijuana Concentrate or Retail Marijuana Product in a single transaction to a consumer. A single transaction includes multiple Transfers to the same consumer during the same business day where the Retail Marijuana Store employee knows or reasonably should know that such Transfer would result in that consumer possessing more than one ounce of marijuana.

To wit: Shops are banned from making multiple sales on the same day that add up to more than one ounce.