Nick Reiner, charged with murdering his parents, Rob and Michele Singer Reiner, spent much of his life battling drug addiction, an affliction that millions of Americans face.
The secretary of state held a marathon news conference, offering little news but more respect for reporters than most others in the Trump administration.
The selection of Scott Beardsley by the G.O.P.-appointed board comes after the previous president resigned under pressure from the Trump administration. A new Democratic-appointed board could try to overturn the choice.
The examination confirmed that the suspect had died from a self-inflicted gunshot wound. His body was found late Thursday in a storage unit in New Hampshire.
The parents of the suspect in the Brown and M.I.T. killings had not seen or heard from him since he left Portugal to enroll at a graduate program at Brown more than two decades ago.