The 21st day of testimony in the Karen Read murder trial will begin at 9 a.m. with the continued testimony of Massachusetts State Police Sgt. Yuriy Bukhenik, one of the principal investigators in the case.

Bukhenik took the stand yesterday, making him only the second member of the agency responsible for the investigation of the homicide of John O’Keefe, other than MSP Crime Lab scientists.

Bukhenik testified to the beginning stages of the investigation, from interviewing witnesses Jennifer and Matthew McCabe and Brian Albert at the McCabe home, to questioning Read and taking her phone and Lexus SUV, to analysis of the the vehicle’s busted taillight and securing security footage from the two bars Read and O’Keefe were at before his death.

Read, 44, of Mansfield, is charged with second-degree murder, motor vehicle manslaughter and leaving the scene of a collision causing death. The charges stemmed from the death of O’Keefe, a 16-year member of the Boston police force and Read’s boyfriend of two years, in the early morning of Jan. 29, 2022.