He allegedly told police that he also hadn't heard from his daughter in the two and a half weeks before Mother's Day.
On their first trip to Bardwell's house, cops spoke with Lowe, who told them that his girlfriend had left earlier that morning - around 8am - in her Acura MDX and that she hadn't been back yet.
Lowe said they had been taking GHB, a common date rape drug, at the time of the incident.
He testified that Bardwell died either late on the night of May 1, 2016, or in the early hours of May 2, 2016.
Lowe, who claims that Bardwell's death was an accident, told jurors on Monday that they had been taking the mind-altering drug GHB before having sex in a shower where she fell and struck her head twice.
He testified that the couple decided to lie down after the fall, but when he woke up, his girlfriend was dead next to him.
As for the dirt on the SUV, Lowe said it was from going 'mudding' recently.
He let police look around apartment, and they left after finding nothing more suspicious.
A Texas man accused of murdering his girlfriend last year re-enacted in court the moment he woke up and discovered her dead body.
Jason Lowe, 28, has been charged with murder in the May 2016 death of Jessie Bardwell, 27, in their Richardson, Texas home.
Defendant Jason Lowe, left, testifies as he answers questions for his attorney Andrew Farkas, right, during his murder trial in the death of girlfriend Jessie Bardwell at Collin County Courthouse in Mc Kinney, Texas, on Monday After Bardwell hit her head, the couple decided to lie down, but Lowe said that when he woke up, his girlfriend didn't move.
He testified that Bardwell died either late on the night of May 1, 2016, or in the early hours of May 2, 2016'I should have called the police,' he told the court, adding that he 'was scared' and 'really made things worse' by putting Bardwell's body in his Audi and later leaving it on a rural property, the Dallas News reported.
Police asked him about the mud, and Lowe said it was from chasing after his dog when it ran away during the search.