The U.S. Postal Services Inspection Service suspected something wasn't quite right with a package destined for the Salvisa Post Office in Mercer County.
And after working with the Mercer County Sheriff's Office, suspicions were confirmed.
Thanks to the sheriff's K-9 unit, the illegal drugs were identified in the package and authorities had what they needed to make the arrest.
According to family of brother and sister Gary and Laura Wiley, the duo went to the post office in Salvisa to pick up the package
Sheriff's deputies were waiting at the family's home when they got back and took them into custody.
Both are being held on a cash bond, totaling $50,000 between them. Both are charged with trafficking marijuana greater than five pounds.
Authorities also recovered a gun, which added a charge of possession of a firearm by a convicted felon.
Investigators believe the package came all the way from California.
Continuing their investigation, authorities were led to another home in Mercer County, this time belonging to Ricky Merriman down Oakland Lane.
Merriman was taken into custody charged with trafficking marijuana and trafficking a controlled substance.
Police also found a large amount of prescription medication, as well as $6,000 in cash.
Police believe both cases are linked, but aren't saying how at this point in the investigation.
Postal Inspector Roberta Bottoms told us mail is inspected daily at each processing center.
Bottoms said the inspector working with closely with investigators on this case was Kyle Erhardt.
Bottoms added shipping illegal drugs through the USPS could carry federal charges.