Most everybody knows it’s illegal to grow or smoke pot. It’s also illegal to have it mailed to you.Two Grinnell residents were arrested Tuesday after trying to pick up a package at the post office — a package filled with an unspecified amount of marijuana. Postal officials thought the package was suspicious and called the Poweshiek County Sheriff’s office, which sent a deputy and a drug-sniffing dog. After a surveillance operation, 24-year-old Jon Seyler Petit is charged with possession with intent to deliver and failure to affix a drug tax stamp, while 22-year-old Lindsay Erin White is charged with possession. More charges may be pending.