Was then-Dallas cop Amber Guyger distracted, or was she merely an exhausted officer on “autopilot” when she went to the wrong floor of an apartment building, entered the wrong unit and fatally shot an unsuspecting 26-year-old Botham Jean in his own home?

These were the questions prosecutors and defense attorneys raised on the first day of Guyger’s murder trial on Monday.

According to CNN, prosecutors argued that Guyger failed to notice several times that she was not where she should be the night of the fatal shooting, including the fact that the garage on the fourth floor where she parked was open-air and her actual parking area on the third floor was not.

There was also a skylight, a neighbor’s decorative planter, and the red mat in front of Jean’s door that allegedly went unnoticed, Jason Hermus, a prosecutor with the district attorney’s office ticked off for jurors.

There was also the fact that once she opened the door to Jean’s apartment, she didn’t seem to recall what her own place looked like (as of course, no two apartments belonging to two separate people are decorated exactly the same), according to NBC News.

There was also the aroma of marijuana that would have been coming from Jean’s apartment that should have alerted Guyger that something was amiss, Hermus added. Jean began using marijuana after he was diagnosed with ADHD, his sister, Allisa Findley testified.

“For her errors, for her omission, Botham paid the ultimate price,” Hermus said.

Jean was sitting at home watching television and eating ice cream when his untimely end came at the hands of Guyger.

Hermus said that the trajectory of one of the bullets showed that Jean was either trying to sit up from the couch or was crouching down when he was shot.

Guyger’s phone records, web searches, and text messages from the night of the shooting which were permitted as evidence revealed that the former cop was in a relationship with Martin Rivera, her partner on an elite crime response team with the Dallas Police.

Records showed that she was on the phone with Rivera when she got into the parking garage, just before the shooting. The call lasted for more than 15 minutes, CNN reports.

Prosecutors also pointed out that Rivera had sent a suggestive Snapchat to Guyger that night, reading, “Wanna touch?” and that the pair had plans to meet up that night according to NBC.

Minutes later, after having shot Jean, Guyger would text Rivera saying “I need you to hurry,” adding “I f–ked up.”

This was was around the time she made a 911 call, repeating some of the same phrases, while also insistently repeating that she thought she was in her own apartment.

Hermus said that this was a sign that Guyger was more worried about herself, rather than a dying Jean.

“When you listen critically to what she is saying, you are going to hear that she is as concerned or more concerned about how this is going to affect her than this poor guy on the floor next to her,” Hermus told jurors.

Defense attorneys meanwhile, argued that Guyger was tired, and working “in autopilot” having asked her supervisor to take a day off the next day after working 40 hours in four days.

“Was that evil of her to do? Was that evil of her not to count the floors? Was that just a reasonable reaction to ‘oh my gosh I found a good spot,'” defense attorney Robert Rogers asked.

“Amber Guyger was in autopilot. She got to the door and she put her key fob and in one motion, the door is opening, and it doesn’t make sense because normally you have to turn the handle,” he added.

Once the door opened, Guyger saw what she believed to be an intruder about 30 feet away from her.

“I’m sure, he’s alarmed. But she’s thinking, ‘Oh my God. There’s an intruder in my apartment.’ And she’s face-to-face with him; she’s within 10 yards of him. And he starts approaching her,” Rogers said, according to CNN.

She drew her gun hoping to deter the supposed intruder, Rogers claimed, who just drew nearer.

Rogers insisted that Guyger “firmly and reasonably believed that she had no choice. She had no options but to use her gun to keep from dying.”

As for her relationship with Rivera, Rogers said that the pair had no plans to see each other, claiming that “the relationship was ramping down” because Guyger was looking for someone “more stable,” NBC notes.

Rivera testified during cross-examination from Rogers that he had never been to his former partner’s residence and had no plans to go there. They were not having a regular sexual relationship at the time, he added.

The messages were “flirting, teasing, mainly,” Rivera said.