The incident happened at Shalimar Bagh in north Delhi.
The woman, in her complaint lodged Tuesday, said that her brother-in-law and his friends raped her, kept her locked in a room for two days and dumped her near the Japanese Park, a few kilometres away from her house at Sector 15 in Rohini.
On May 19 afternoon, her brother-in-law called her at his jewellery shop to talk on some issue. When she reached there, his four friends were also present. They offered her a drink laced with sedatives and raped her in turns.
A case has been registered and the allegations are being probed, said an officer.