Last summer, an unexplained phenomenon gripped nightly newscasts and Facebook groups across America: Unsolicited deliveries of obscurely labeled seed packages, seemingly from China, were being sent to Americans’ homes. Recipients reported the packages to local police, news stations, and agriculture departments; searched message boards for explanations; and theorized about conspiracies including election interference and biowarfare. Despite large-scale USDA testing of the packages, the mystery remained: Who sent the seeds and why?

This week on The Experiment podcast, the host Julia Longoria speaks with the writer Chris Heath about his investigation of mystery seeds for The Atlantic, the byzantine world of international e-commerce, and the dangers of both panic and reason. 

Further reading: “The Truth Behind the Amazon Mystery Seeds.” This article is part of “Shadowland,” a project about conspiracy thinking in America.

A transcript of this episode is available. 

Be part of The Experiment. As #TheExperimentPodcast keeps growing, we’re looking for new ways to tell stories and better serve our listeners. Please visit theatlantic.com/experimentsurvey to share your thoughts with The Atlantic and WNYC Studios.

Use the hashtag #TheExperimentPodcast, or write to us at theexperiment@theatlantic.com.

This episode was produced by Katherine Wells and Julia Longoria, with help from Honor Jones. Fact-check by William Gordon and Michelle Ciarrocca. Sound design by David Herman and Hannis Brown.