Narendra Gurjar alias Fauzi was arrested from Sahibabad on Sunday, they said, adding a pistol, four live cartridges and a motor cycle without registration number plate were seized from his possession.
Senior Superintendent of Police H N Singh said four teams of police under the aegis of S P (City) Akash Tomar were formed to arrest the accused.
Bhati was killed and his friend injured when unidentified assailants fired at them on September 2.
According to the police, former BSP MLA of Sahibabad, Amarpal Sharma had allegedly given the accused Rs 10 lakh for eliminating the BJP leader over political rivalry.
During interrogation, the accused allegedly told the police that Bhati was intending to contest the election for the post of chairman of the newly-formed municipality of Khoda.
Efforts are on to arrest the former BSP MLA, police added.