After the state rested, the defense called Grayson as its first witness.
Grayson was questioned and cross-examined Monday morning in Peoria.
At the start of the second week of the trial, Grayson took the stand for roughly an hour around 9 a.m.
He testified he was called to Massey's home last year about someone outside her residence.
The key piece of evidence in the trial is the body camera video from the vantage point of another deputy. Grayson's body camera was never on, a point he addressed during his testimony. He clarified to the jury that when he started questioning Massey about a smashed window on a car in her driveway, he should have turned it on, and believed he had at that moment.
Once inside, Grayson told the jury he heard a noise near the stove and saw a burner on, with the bottom of a pot turning red. Grayson says he asked the other deputy to turn off the stove, but once the deputy moved toward the kitchen, he says Massey jumped up and followed him.
The situation gradually intensified at that point, as the body camera footage shows. Grayson said Massey picked up the pot with oven mitts on and started walking toward him before setting it on the counter. As Grayson and the other deputy stepped back, the tension escalated quickly.
Massey: "Where ya going?"
Officer: "Get away from your hot, steaming water."
Massey: "My hot steaming water?"
Officer: "Yeah."
Massey: "Oh, I rebuke you in the name of Jesus."
Officer: "Huh?"
Massey: "I rebuke you in the name of Jesus."
Officer: "You better (expletive) not. I swear to God, I'll shoot you in the (expletive) face."
Grayson then shot Massey in the face three times. During his testimony he says he perceived Massey's words and actions as a threat, telling the courtroom "we are trained to use force to gain compliance. I matched the threat level."
Grayson admitted when Massey crouched down behind the counter, she showed that she was willing to comply. Grayson said he stepped forward intending to handcuff her for aggravated assault, but as he approached he says Massey looked at him and started to stand.
Grayson clarified that he shot Massey only when she raised her hands to throw the pot at him. The body camera footage does not show Massey at the moment Grayson describes.
He said he considered using a Taser, but was worried it wouldn't work.
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Grayson said Massey was wearing multiple layers of clothing and standing diagonally.
During cross-examination, the state's attorney questioned Grayson about his intention to handcuff Massey, calling it new information that was never in his report. There was also no record of Grayson's expletive-laced demand of Massey before firing his weapon.
In addition to Grayson, several use-of-force and de-escalation experts were called to testify.
Just after 3 p.m., the defense rested its case.
Closing arguments are set to begin Tuesday.
Grayson, 31, has pleaded not guilty. If convicted of murder, he faces 45 years to life in prison. Prosecutors dismissed single counts of aggravated battery with a firearm and official misconduct.