After four MDMA-related deaths and scores of overdose in New York, Boston, and DC last weekend, investigators are now trying to figure out whether the adverse reactions were all tied to a single bad batch.

At least four people died after taking molly last weekend; Brittany Flannigan, 19, overdosed at Boston's House of Blues; Jeffrey Russ, 23, and Olivia Rotondo, 20, overdosed at the Electric Zoo Music Festival in New York; and Mary "Shelley" Goldsmith, 19, overdosed at a nightclub in DC.

Molly, another term for MDMA, comes from the word "molecular" and is supposed to connote purity. In actuality, however, molly is usually cut with substances as innocuous as baby powder or as harmful as rat poison. Whether due to poor quality or merely the drugs' new ubiquity, however, poison control centers have reported an uptick in MDMA cases.

But even if there is a bad batch floating around, it's unlikely that all the deaths were tied it. Although investigators say the Boston overdoses were tied to molly bought out of state, Rotondo allegedly told EMS workers before she died that she had taken six hits, and police believe that Russ took a different set of drugs.

[image via Shutterstock]