MONROE — Incorrect packaging appears to have undone an illegal shipment of marijuana.

The Monroe Police Department is investigating a box containing more than 5 pounds of marijuana that was shipped from a private parcel business. The package reportedly made it to Arizona via FedEx before being returned to Mail Station in Monroe the next day because it had a “placard” on its side that excluded it from air mail.

Once it was returned, the owner of Mail Station opened the package to discover the marijuana and alerted Monroe police.

“He didn’t realize when he got the box,” Monroe police spokeswoman Debbie Willis said Tuesday. “He just opened it up and realized it was the one he sent the day before.”

The incident is under investigation to determine who sent the package. Willis said the police are looking for two men who dropped it off at Mail Station.

Marijuana, while legal in Washington, is still illegal in many other states. Mailing it is a crime, even if purchased legally, Willis said.

“Going out of state, you shouldn’t be doing that,” she said.

For reference, retail marijuana is typically sold in grams and ounces. A typical joint has a half gram or a gram of marijuana in it. There are nearly 2,268 grams in 5 pounds of marijuana.

This box sent via FedEx from Monroe to Arizona was returned to the Mail Station the next day as it had a "placard" on the side of the box that excluded it from air mail. Mail Station owner opened it up to find…. pic.twitter.com/OAtAXNDnzY

— Monroe PD (@MonroePolice) April 2, 2018