Ankit Das, said to be a close friend of Ashish Mishra, turned up before the special investigation team (SIT) at the crime branch office in Lakhimpur on Wednesday, police said.
The investigators had summoned Das for questioning in connection with the October 3 violence which had left eight people, including four farmers, dead.
At around 11 am, Das along with a team of lawyers arrived at the reserved police lines in Lakhimpur and reached the crime branch office located there, police said.
On Tuesday, Das and one other identified as Latif had moved an application for surrender at the court of the chief judicial magistrate.
Das is the nephew of former minister late Akhilesh Das.
Also read: Lakhimpur Violence: Ashish Mishra's friend Ankit Das files surrender application in court
The SUV which was behind the car that knocked down the four farmers is said to be owned by him.
Police have so far arrested four people in connection with the case.
While one person, Shekhar Bharti was arrested on Tuesday, minister Ajay Mishra's son Ashish Mishra, Luvkush and Ashish Pandey were arrested earlier.