Boston litigation boutique Dwyer & Collora can trace its civil litigation work for dialysis services company Fresenius Medical Care North America to a white-collar defense assignment for an executive of a company Fresenius eventually bought.

During that case several years ago, Dwyer & Collora partners Bill Kettlewell and Maria Durant formed ties with Ron Castle of Washington, D.C.’s Arent Fox. Fresenius wasn’t a party to the criminal case but was keeping an eye on the court proceedings. When Castle became deputy general counsel in charge of litigation at the Waltham, Mass.-based Fresenius in 2004, he called Dwyer lawyers for advice on restaurants, where to live and, most importantly, for help in court. The firm has since helped Fresenius with business cases in such far-flung jurisdictions as Hawaii and New Jersey, usually when the case is about to go to trial, Durant said.