The accused were arrested from their residences in Johalka village near Sohna in Gurgaon.
A woman was allegedly sexually assaulted while her husband and brother-in-law were being held at gun-point at Sector-56 in Gurgaon, following which four persons were arrested, the police said.
Police said the incident occurred late last night when the 22-year-old woman was returning from a family function along with her husband.
According to the woman, while returning in her brother-in-law's car, they stopped near Business Park Tower in sector 56, where her husband stepped out of the vehicle to use the toilet.
In the police complaint, the woman said two cars pulled up there and four persons asked them the reason for stopping their vehicle there.
The accused then dragged her out of the car and while three of them held her husband and brother-in-law at gunpoint, the fourth one raped her, said Manish Sehgal, ACP and chief PRO of Gurgaon police.
Before fleeing, they threatened the victim, her husband and brother-in-law with dire consequences if they approached the police, Mr Sehgal said, adding the woman's husband managed to note down the registration number of their one of cars.
"The accused were arrested from their residences in Johalka village near Sohna in Gurgaon and a case under relevant sections of the IPC have been registered against them," the officer said.