Tipu Sultan, 32, was found with a single gunshot wound on Tuesday at the back of the Herbs n Spice Kitchen, where he worked in South Shields.
Police said they arrested a 35-year-old Newcastle man on Sunday afternoon.
Earlier, officers searched areas including a golf course, along a route which they think a motorbike seen leaving the area may have followed.
Mr Sultan was shot at close range, in what police believe was a planned killing. He was treated by paramedics but died at the scene.
His family have run the restaurant in Lake Avenue for more than a decade.
Two men riding a large red high-powered motorbike were seen leaving the area immediately after the shooting.
Detectives said several areas had been searched on Sunday along the route the bike is thought to have travelled, including Whitburn Golf Club.
Footage taken from a CCTV camera showed the bike heading along Lizard Lane towards the course at 21:55 BST on Tuesday.
Det Ch Insp John Bent of Northumbria Police said the force had received a "very positive" response to an appeal for information from the public, and was following up several calls.
"We'd still appeal for anyone who thinks they may have information about the motorbike or the two men to come forward and speak to officers," he said.
A man has been arrested on suspicion of conspiracy to murder by police probing the killing of a man near a takeaway.