Saira Begum, 45, and her husband Afaq Hussain, 50, were arrested along with Ramesh Pandey and Vasudev Pandey -- both residents of Nepal, Shamshad, Pooja and Mumtaj on August 25.
Sarfaraz, one of the main accused and muscle man, is still absconding.
Police said a case was initially registered on August 19 under the stringent Maharashtra Control of Organised Crime Act (MCOCA) and investigations launched to nab the accused.
Police said the couple ran a sex racket for the past almost 17 years and their syndicate was suspected to have trafficked more than 5,000 girls from Nepal and remote areas of West Bengal, Odisha, Karnataka, Assam and Andhra Pradesh, among other states.
Begum and Hussain, who were earlier arrested by the Crime Branch in 2013, used to reside at another place but were controlling the organised racket with the help of different paid managers, nayikas (mistress) and traffickers.
"All these nayikas helped the couple in running the management of brothel. Hussain paid them 15 per cent of the earnings for their role," Joint Commissioner of Police (Crime Branch) Ravindra Yadav said.
Investigators said the couple had purchased the brothel premises at G.B. Road in central Delhi in 2003 but later transferred the ownership to some of their associates to avoid legal action.
"In this manner, the couple had planned to continue their illegal activities unabated without the fear of being nabbed and amassed disproportionate wealth to the tune of crores of rupees from this illegal trade," the officer said.
The officer said that four luxury cars and Rs 9 lakh in cash were recovered from the possession of the accused. "They also own several flats and houses in Delhi and Bengaluru."
"The accused control and carry forward the illegal business of human trafficking and prostitution, and have been receiving earnings from the business of commercial sexual exploitation since 1999," the officer said.
Police said Saira Begum, who hails from Hyderabad, came to Delhi with her first husband Talaf Hussain after the death of her parents and started working as a sex worker in G.B. Road area when she failed to get a job for over a month.
She gradually started a racket of commercial sexual exploitation at brothel No.58 at G.B. Road where she was a sex worker. It was the same brothel where Saira Begum came in contact with Hussain, who hails from Moradabad in Uttar Pradesh.
Police said Hussain was attracted by Begum's huge earnings from her prostitution racket and he offered to marry her. They married in 1999. After that, they started assisting each other in carrying out illegal activities of immoral trafficking with the help of various associates.
