Massachusetts State Police Trooper Michael Proctor, the lead investigator in the Karen Read murder trial, will return to the stand today for what promises to be a tense cross-examination by defense attorneys.

“These regrettable and unprofessional comments are not something I’m proud of and are not something I should have written in private or any other setting,” Proctor said Monday in one variation of a repeated apology for crude language he used in private texts to describe Read while he was investigating her.

The comments include calling her a “whack job” as well as more offensive language, with one word so harsh — a derogatory word that refers to women’s genitalia — he attempted to spell it out in the court room before Judge Beverly Cannone told him that he wrote it so he should read it as it is.

Read, 44, of Mansfield, faces charges of second-degree murder, motor vehicle manslaughter and leaving the scene of a collision causing the death of John O’Keefe, a 16-year Boston Police officer when he died at age 46 on Jan. 29, 2022.

Her trial began April 29 in Norfolk Superior Court in Dedham and has already gone on six weeks. Today will be the 23rd trial day.

This is a developing story.