Defense witness Andrew Rentschler of ARCCA on the stand during the Karen Read retrial in Norfolk Superior Court, Wednesday, June 11, 2025, in Dedham, Mass. Greg Derr/The Patriot Ledger via AP, Pool ...

Andrew Rentschler, a biomechanical engineer and accident reconstructionist from ARCCA, began testifying on Tuesday and returned to the stand on Wednesday for the 31st day of testimony in Read’s ...

Wednesday featured a tense cross examination, with Special Prosecutor Hank Brennan sparring with the defense’s crash expert, Dr. Andrew Rentschler from ARCCA.

Andrew Rentschler, a biomechanist and accident reconstruction expert, delivered potentially critical testimony about his analysis of O’Keefe’s head, brain and body injuries.

Andrew Rentschler, a biomechanist and accident reconstruction expert, is expected to testify about his analysis of what caused Boston police officer John O’Keefe’s head, brain and body injuries.