Absconding since February 27, Prajapati was arrested in Lucknow's Aashiana area early on Wednesday by a joint team of the Special Task Force and the local police.
Sources told IANS that the mining minister in the outgoing government, known for his proximity to Samajwadi Party (SP) founder Mulayam Singh Yadav and Chief Minister Akhilesh Yadav, was first taken to the Alambagh police station for recording his statement.
The police has already arrested other accused, including Amrendra Singh aka Pintu, Roopesh and Vikas Verma, gunner Chandrapal, a revenue official Ashok Tiwari, Ashish Shukla and had detained the sons of the minister.
Prajapati apparently came under pressure after two of his sons were detained by the Uttar Pradesh Police on Tuesday.
Prajapati unsuccessfully contested the recent state assembly elections from Amethi. He had won from there in 2012. Six others accused in the same case were held earlier.
In February, the Supreme Court had ordered the state police to lodge an FIR against him. The gang rape victim had accused Prajapati's henchmen of terrorising her and her daughter in a Delhi hospital.
Uttar Pradesh Director General of Police Javeed Ahmad said Gayatri was being tracked for some time and that he was constantly changing his locations.
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