In December 2021, Rittmanic, 49, and then-Officer Tyler Bailey were shot after approaching a man who was wanted on a warrant for his arrest.
They had responded to the Comfort Inn off of Route 50 that night after a complaint about barking dogs in a car.
Prosecutors allege Darius Sullivan shot the officers as they confronted him at his hotel room door.
Bailey was seriously injured but survived. Rittmanic was honored by officers and civilians at her funeral and was buried at the Abraham Lincoln National Cemetery.
Sullivan and Xandria Harris are charged with murder and attempted murder.
The couple was allegedly in the hotel room with two of their three children. Sullivan is also charged with endangering the lives of children.
Harris will be tried separately.
Jury selection began Monday in Sullivan's trial. Opening statements are expected Wednesday.
Before prospective jurors were brought in Monday, Sullivan had an outburst.
His attorney explained he was upset that his minor son could be called as a witness. Prosecutors confirm the child is among dozens of potential witnesses in the case, which is expected to last two weeks.