Federal agents briefly detained former Steward Health Care CEO Ralph de la Torre early last week, served him with a search warrant, and seized his phone — the latest sign that a federal corruption probe is focused on the healthcare chain's embattled founder, according to three people briefed on the matter. Another Steward executive, Armin Ernst, a Brookline resident who leads Steward's international entity, was also recently visited by federal investigators and had his cellphone seized, two of the people briefed told the Globe. The searches come on the heels of a Globe Spotlight Team report that revealed several Steward board members had been summoned to answer questions as part of a sprawling grand jury probe into alleged fraud, bribery, and corruption within the now-bankrupt, Boston-born healthcare chain.
