The couple did not inform the police about the sexual violence initially.
Five men were arrested in Tamil Nadu's Sivaganga district on Thursday for allegedly gang-raping a woman, police said.
Investigators say the woman's male friend was first attacked by two men when the couple was at a farm on Tuesday. Later, at least three other men joined and sexually assaulted the woman.
The couple did not inform the police about the sexual violence initially. The man who had sustained minor injuries had only registered a mobile snatching complaint against the gang.
It was during interrogation police learnt about the rape. The next day, on September 18 the woman filed a police complaint against the suspects leading to the arrest of five men.
"Medical examination has been completed. It confirms sexual assault. Three men had sexually assaulted her. We are investigating if there were any others involved," a senior police officer told NDTV.