DES MOINES, Iowa (AP) — Attorneys for nine patients have filed a lawsuit against Iowa Methodist Medical Center, blaming the hospital for a pharmacy tech’s theft of potent painkillers from hundreds of vials. The Des Moines Register reports that the lawsuit accuses the hospital of being negligent in its supervision of the pharmacy tech who stole fentanyl and Dilaudid during a six-week period last year.

The hospital contacted more than 700 patients last October after learning of the tampering, fearing the patients might not have received full doses of the drugs. The attorneys say there are 185 former patients whose pain medication was diluted who are willing to take their cases to court and expect more to sue in the coming weeks.

Hospital spokeswoman Amy Varcoe denied several allegations in the lawsuit Friday.