He also quizzed him about comments he allegedly made that Ross deserved to have her family burned in front of her.
"Sounds like something I'd say," Merritt said.
Det Smaill also pointed out scratches to the defendant's face and arms, which the suspect explained must have been self-inflicted in his sleep.
"You've got pretty short nails. How did you manage to scratch yourself in your sleep?" the officer said.
"I just woke up with scratches," the defendant said.
Merritt told him a similar incident had happened once in the past, when he awoke with scratches on his back.
"I just thought it was weird," he said.
The detective had also pointed out a bruise under Merritt's eye but defence lawyer Anne Stevens suggested that was simply shadowing.
The cross examination eventually saw the witness approach the dock to look closely at the defendant's face.
The officer told the court there was a shadow under the right eye today but not the yellow colouring he appeared to have at the time of questioning 10 months ago.
Det Smaill outlined his concerns about Merritt's version of events.
"We've got Karin Ross who's got all these injuries and we've got you the morning she was found . . . waking up with scratches on your forehead, left arm and on your right hand and you're saying it happened when you were asleep?"
Merritt stood by his explanation.
Crown and defence are expected to close their respective cases today before the judge summarises the case and the jury begins deliberations tomorrow.
