Dr. Robert Huizenga, O.J. Simpson's personal physician, testified as a defense medical witness in July 1995 about Simpson's physical ailments and his June 15–17 examinations. During Brian Kelberg's multi-day cross-examination, Huizenga was questioned about his qualifications and documentation, letters discussing litigation strategy, exercise videos, medical records, and whether Simpson's arthritis imposed physical limitations; Huizenga also said he had lost sleep after regretting an earlier answer about what a cold-blooded killer might be capable of doing. In the civil trial, Huizenga testified that Simpson's hand injuries fell within a five-to-seven-day range that included June 12, 1994.