Johannes Christiaan de Jager, 49, testified that the 16-year-old, who lived with him and his girlfriend in Kraaifontein, Cape Town, hardly ever left her room and was anti-social.
He has pleaded not guilty to killing Mare on January 11 last year. He has also denied raping and killing prostitute Hiltina Alexander, 18, in Cape Town in May 2008.
On the morning before Mare’s death, the domestic worker arrived and wanted to remove linen from her bedroom.
De Jager said he went to Mare’s bedroom and tried to wake her up, which was “the same story” every morning.
“The room was full of dog faeces, and it was on the linen too. That’s when I scolded her and said no one can live like this, like a pig,” he testified in Afrikaans.
His lawyer asked if he had told Mare she was “fucking useless”.
“That’s correct, because of the condition of the room,” De Jager replied.
In a cellphone message to a friend that day, Mare said De Jager had told her she was “fucking useless” after he asked her to do something and she ignored him.
De Jager said he and a friend went to look at his cousin’s car in Bellville that evening.
“We started drinking a lot there. If you look at volumes, between myself and Carlo, it would be six litres.”
He drank brandy and whisky. He returned home around 11pm, made himself food and fell asleep in front of the television.
He woke up around 6am that Friday.
The trial continues.