The incident was reported around 6 pm Monday after the victim telephoned the Police Control Room.
"The victim made the allegation against her husband, husband's lawyer, a clerk, and her husband's brother-in-law. A case regarding the incident has been registered after victim's medical report and probe is on into the incident," said S B S Tyagi, deputy commissioner of police.
Police were checking the CCTV footage of both the courts and the call details of the woman and others to investigate the case.
The victim told police that she was raped inside a lawyer's chamber at the Patiala House Court complex Monday evening.
The woman, a resident of Pandav Nagar in east Delhi, said that after marital discord with her husband she had filed a divorce case which was being going on at Karkardooma court in east Delhi.
She alleged that her husband's lawyer called her at Karkardooma court to settle the issue Monday afternoon, where her husband's sister and brother-in-law were already present.
"After talking at Karkardooma court for hours, the lawyer asked them to come to Patiala House court. She reached Patiala House court and went to lawyer's chamber number six where her husband offered her beer which she refused. After that all the accused gangraped her," police said, quoting the victim's complaint.
The accused later threatened her of dire consequences, police said.