Crown attorney Bev Richards hammered accused killer Kalen Schlatter with questions in court Tuesday, during cross-examination at his trial for first-degree murder in connection with Tess Richey's death.

Over the course of several hours, Richards zeroed in on multiple "coincidences" within Schlatter's testimony where, she says, things didn't add up.

"You left her there dead, isn't that right, Mr. Schlatter?" Richards said. Schlatter flatly denied that, and said Richey was alive when he left her after they had made out in an outdoor stairwell in the city's gay village in 2017.

"You knew very well what you had done, and you left her there," Richards said.

With her voice booming inside a packed courtroom, Richards pointed out several instances in which Schlatter said he lied during his testimony — both to friends and to undercover police officers.

"Mr. Schlatter, you lie to strangers, fair?" Richards said.

"I lie for specific reasons," Schlatter responded.

He appeared flushed through much of the cross-examination, and verbally stumbled at times. He told court Monday that he has a speech impediment that sometimes causes him to slur his words.

Schlatter also said he lied while in a holding cell after his arrest with two undercover police officers he thought were criminals. He testified he inflated the number of women he had slept with while talking to them in order to hide the fact that he is bisexual.

"I lied to protect myself," Schlatter said.

"Yes, you do that, don't you?" Richards shot back.

Schlatter's DNA found on Richey's clothing

For over five weeks, the jury has heard witness testimony about the 23-year-old Toronto man, who the Crown alleges sexually assaulted and then strangled Richey before leaving her body at the bottom of the outdoor stairwell.

Schlatter has pleaded not guilty in connection with the 22-year-old's death.

Schlatter has pleaded not guilty to first-degree murder. (Facebook)

Court has heard Schlatter's semen was found on Richey's pants and his saliva was on the inside of her bra.

The jury has also seen security camera footage of Schlatter and Richey together in the early morning hours of Nov. 25.

That includes video showing the pair walking up a driveway to the outdoor stairwell where her body was later discovered at 582 Church St., before Schlatter emerges alone about 45 minutes later, heading back the way they came.

"You never look back, do you, Mr. Schlatter?" said Richards, after showing video of that moment in court.

"No, I don't," he said.

WATCH: Kalen Schlatter and Tess Richey walk up driveway

This footage of Kalen Schlatter and Tess Richey was played at Schlatter's first-degree murder trial. The two can be seen walking together down an alleyway. Schlatter leaves on his own some time later. 0:24

Schlatter said Richey was the one who took the lead that morning, initially asked him to kiss her, and eventually told him to follow her up the driveway.

Richards countered by saying the security footage doesn't back up that argument. She showed video from earlier in the morning, where Richey appeared to try to hail a cab while with Schlatter and her friend Ryley Simard, after leaving drag club Crews and Tangos.

"She wanted to go home, didn't she?" Richards said. Schlatter responded that he didn't know if the cab was for Richey or Simard, but he eventually waved it on because the driver was holding up traffic.

"I wasn't stopping anyone from getting in that cab," Schlatter said.

Kalen Schlatter's family, left, sits in court with Justice Michael Dambrot, centre left, Schlatter, centre right, and assistant Crown attorney Bev Richards, right. (Pam Davies/CBC)

Richards also showed video of Schlatter milling about in the crowd outside the club after last call. She pointed to various interactions he had with women as indicative of him trying to pick someone up.

"That's what you do, Mr. Schlatter. You just hang on the outskirts, waiting, don't you?" Richards said.

Schlatter again denied that.

'She was alive when I left her'

Schlatter testified that once he and Richey were in the stairwell, they made out for a while before he got down on his knees and she started "grinding" on him, before he eventually "came in his pants."

Schlatter said he later asked Richey if she wanted to come back to his family's home, but she declined.

He testified Richey then pulled out her phone and told him he could leave, so he left her at the stairwell. Richards challenged Schlatter about exactly where he said Richey was when he left, and said he "can't get his story straight" because Richey had actually been "strangled to death at the bottom of the stairwell.

"That's where you left her, isn't it Mr. Schlatter?" Richards said.

"She was alive when I left her," he responded.

CBC Toronto reporter Adam Carter reported live from inside the courtroom Tuesday morning. You can read a recap here:

adam.carter@cbc.ca