The victim was employed as domestic help by accused Benjamin, who had retired as cook, they said.
Police said Benjamin allegedly wrongfully confined and sexually assaulted the girl twice in August last year, but the matter came to light only yesterday after it was detected that the victim was pregnant.
Police said the victim's mother had taken her to a nearby hospital for examination after the former complained of stomach pain.
"The minor girl informed to her mother that the ex-serviceman raped her at his house on two occasions and had even tied her with a rope before committing the crime," a police officer said based on a complaint lodged by her mother.