"The grandfather of a 5-year-old girl was allegedly sexually molesting her and his wife aided and abetted his heinous crime," a senior police officer said.
The elderly couple was arrested from Mumbai yesterday, a week after the complaint filed by the victim's parent, and brought to Gurgaon, he said.
They were produced in the court.
A case under relevant sections of IPC and POCSO was registered on June 28 at women police station.
The investigation is going on, the officer added.