CBI arrested two young men -- brothers Ajay and Vijay Pal -- from Balipur village of the Kunda area in Pratapgarh on charges of murdering village head Nanhe and his brother Suresh Yadav, sources said.
CBI sources said that evidence indicated that the two would emerge as prime accused in the sensational double murder of March 2, which triggered major violence in the village and led to the brutal killing, hours later, of deputy superintendent of Police Zia-ul-Haq.
The arrests were made on Sunday. The first arrests, however, have no linkage to the killing of the police officer, sources said.
The country-made pistol and empty shells used in the murders have also been recovered by the CBI, officials said.
A mobile phone, sim card and the conversations on phone after the murders is crucial evidence, which led to the arrests, an official told IANS.
The men are sons of Kamta Pal, a local strongman who had a long-standing animosity with the slain village head.
Dharini Mishra, spokesman of the CBI said: "A deep-rooted conspiracy cannot be ruled out in the case".
In a related development, the state government is likely to dismiss a senior inspector and a few cops for leaving Haq all alone before an unruly mob, which resulted in his death.
"The departmental probe against these people has been completed and a report submitted to the government. We hope to see these coward policemen dismissed from service and later arrested," a senior home department official told IANS.
The bodyguard of the slain DSP had also fled the scene of crime when an irate mob lynched and then shot Zia-uld-Haq.
The 40th day rituals of the slain police officer would be held at his native village in Deoria on April 9.
His widow, Parveen Azad, has demanded more security cover for her family, and has expressed satisfaction with the CBI probe, so far.
"Let me see what comes out in the end, so far I am satisfied. If justice is not done, I will continue to fight," she said.