Karen Read exchanged flirty texts with another man two weeks before her cop boyfriend was found murdered, according to testimony Friday.

Text messages between defendant Karen Read and ATF agent Brian Higgins are essential to understanding the theories behind both the prosecution and defense’s case.  Read all of them here.

Massachusetts State Police Sgt. Yuri Bukhenik spent a third day on the stand Monday in the Karen Read murder trial, facing extensive questioning from both sides of the case.

Private text messages between Karen Read and an ATF special agent were read aloud for the jury during her retrial. The messages were also apart of her first trial last year. NBC News' Kathy Park has the latest on the trial.

The ongoing trial is Read’s second; her first murder trial ended in a high-profile mistrial last July after jurors returned deadlocked. Abby Patkin is a general assignment news reporter whose work touches on public transit, crime, health, and everything in between. She has been covering the Karen Read murder case.

After flirty text messages surfaced between Karen Read and Brian Higgins, the trial took a shocking turn—raising questions about whether jealousy was a motive for the murder of John O'Keefe.