The 46-year-old was apprehended on the R102 near Voorbrug on Tuesday night, Captain Malcolm Pojie said.
The man had been wanted by police and was arrested after a tip-off that he was going to Bloemfontein.
The man and an accomplice allegedly attacked a 56-year-old woman at her house in Sandhoogte Road on Monday. Pojie said she was threatened with a knife and the men demanded money.
“[The man] slit her throat with the knife when she refused to show him where the safe was.”
The woman then showed the men the safe and they took an undisclosed amount of money before running away. The woman was taken to hospital in a serious but stable condition, said Pojie.
The arrested man was allegedly found in possession of more than half the stolen money. He would appear in the Mossel Bay Magistrate’s Court on Friday.
Police were searching for his accomplice.