After being detained for 15 days, slain gangster Vikas Dubey's close aide Jai Bajpai and one of his accomplices were arrested on Monday morning, police said.

The arrests were made on charges of criminal conspiracy and helping Dubey in his nefarious design by providing him cash and cartridges hours before the Bikru village ambush, in which eight police personnel were killed and seven others, including a civilian, left seriously injured, the police said in a statement issued here.

A police probe revealed that Dubey had made a phone call to Bajpai on July 1. The next day, along with his aide Prashant Shukla alias Doublu, a resident of Kohna, Bajpai went to Bikru to hand over Rs 2 lakh in cash and 25 cartridges of .32 bore revolvers to Dubey, the statement said.

Dubey had briefed Bajpai about his plan to launch an attack on the police party that had gone to the village to arrest him. He had also asked Bajpai to arrange for at least three sports utility vehicles (SUVs) for him and his gang members.

Accordingly, Bajpai took three SUVs to pick up Dubey and his men and take them to safer places, but failed to do so due to intensive police patrolling, the statement said.

On July 4, Bajpai left his vehicle in the Kakadev area and went underground, a police official said.

Soon after seizing the three vehicles, police raided the possible hideouts of Bajpai and nabbed him within hours, a senior official said on the condition of anonymity.

Subsequently, he was handed over to the Special Task Force (STF) of the Uttar Pradesh police and taken to its headquarters in Lucknow, where he was kept in detention for 15 days, the official said.

Bajpai was handed over to the Nazirabad police on Sunday and subsequently let off, another official said, adding that he was arrested again following frequent tweets and posts on social media platforms about his release.

A police communique confirmed that Bajpai and Shukla were booked under sections 147 (punishment for rioting), 148 (rioting, armed with deadly weapon), 149 (every member of unlawful assembly guilty of offence commit ted in prosecution of common object), 302 (murder), 307 (attempt to murder), 395 (Punishment for dacoity), 412 (dishonestly receiving property stolen in the commission of a dacoity) of the Indian Penal Code (IPC) and section 7 of the Criminal Law Amendment (CLA) Act read with section 120B (criminal conspiracy), IPC.

A separate FIR under sections 29 and 30 of the Arms Act has also been registered against Bajpai for providing cartridges to Dubey illegally, the police statement said.

Dubey, the prime accused in the killing of the eight policemen in Kanpur's Bikru village on July 3, was killed in a police encounter on July 10.