Dr. Andrew Rentschler, a biomechanical engineering specialist with ARCCA, was called to the stand Tuesday afternoon after Dr. Elizabeth Laposata, who believes John O’Keefe’s injuries were ...

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

Andrew Rentschler testifies on the injuries John O'Keefe received when he died at the Karen Read retrial, Tuesday, June 10, 2025, in Dedham, Mass.

Andrew Rentschler testifies on the injuries John O'Keefe received when he died at the Karen Read retrial, Tuesday, June 10, 2025, in Dedham, Mass.

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.

Andrew Rentschler, a biomechanic engineer hired by the defense, told jurors Laura Dankesreiter’s story cannot be believed. Rentschler said that because the trip wire was placed 2 inches above ...