Eyewitnesses have claimed the Tunisian beach massacre may have been carried out by more than one attacker as authorities continue to quiz seven suspected associates of the gunman.
Authorities say Rezqui acted alone during the rampage in the resort of Sousse but had accomplices who supported him before, providing him with weapons and logistical support.
But British tourists staying in the north African country claim they saw a second man carrying a gun and roaming the resort.
Steve Johnson, a retired police officer, was on holiday with his wife Valerie and fellow ex-officer Michael Perry and wife Angela.
He told the Daily Mirror: “We were on the beach when I heard gunshots and screaming and I told people to ’run’ and got off the beach as fast as I could. We were really close and I could hear the constant noise of an automatic weapon. I saw a man in red shorts machine-gunning someone on a sun lounger. He was 20 yards away from us.
“We ran across wasteland and into a spa and hid in the basement while gunshots and grenades and everything was going off around us. After about 20 minutes we crept up to the third floor and we could see him shooting people around the pool. It was 40 minutes later when a Tunisian policeman came to get us and he took us through a corridor from the spa to the hotel.
“On the floor was a body, covered mainly with a sheet, but I could see he was the right build and colouring of the shooter I had seen. And he had red shorts on ... Mick had seen both gunmen and we are sure there were two of them.”
Mr Perry told the paper he had seen the bare-chested gunman running with a weapon.
When he asked a police officer what had happened to the attacker, he was reportedly told: “We shot him”.
Rezqui, dressed in black, appeared to be alone in the video footage of the atrocity that has emerged so far.
The seven people in custody were arrested in at least three different cities and taken for questioning in the capital Tunis.
A total of 38 people, including three Irish citizens, died after 23-year-old student Rezgui opened fire on Friday. The self-proclaimed Islamic State (IS) - also known as Isil – later claimed responsibility.