The arrested were identified as Rohit Kumar, Vijay Kumar Gupta, Rajesh Kumar, Ishu Kumar and Sonu Kumar Gupta, the ADG said.
He said Rohit Kumar has admitted that he fired on the scribe resulting in his death.
Search is on for some more persons involved in the crime, he added.
The police have also seized a 7.65 bore country-made pistol and three motorcycles used in the crime, he added.
Rajdeo Ranjan, district bureau head of a leading vernacular newspaper, was shot dead by unidentified men, when he was going on his motorcycle near fruit market on station road under town police station area of Siwan on May 13 evening.
The killing had drawn country-wide criticism for Nitish Kumar government as a reflection of the slide in law and order situation in the state.
Business Standard has always strived hard to provide up-to-date information and commentary on developments that are of interest to you and have wider political and economic implications for the country and the world. Your encouragement and constant feedback on how to improve our offering have only made our resolve and commitment to these ideals stronger. Even during these difficult times arising out of Covid-19, we continue to remain committed to keeping you informed and updated with credible news, authoritative views and incisive commentary on topical issues of relevance.
We, however, have a request.
As we battle the economic impact of the pandemic, we need your support even more, so that we can continue to offer you more quality content. Our subscription model has seen an encouraging response from many of you, who have subscribed to our online content. More subscription to our online content can only help us achieve the goals of offering you even better and more relevant content. We believe in free, fair and credible journalism. Your support through more subscriptions can help us practise the journalism to which we are committed.
Support quality journalism and subscribe to Business Standard.