And the appeal, which aired on BBC One at around 10am today, revealed for the first time that the male suspect told the 15-year-old victim his name was Davi and that he was from Birmingham.
Rav Wilding, presenter of the show, called the attack “truly sickening and distressing” but, as Dorset Live reports, no arrests have been made at this stage.
Speaking on the programme, Detective Inspector Wayne Seymour, of Dorset Police, said the force are “very confident” in eliminating other potential suspects due to new DNA evidence.
Mr Wilding emphasised how this should make people confident to come forward with information – anyone whose DNA does not match can be ruled out of the police investigation.
Dorset Police last month released an e-fit image of their suspect, described as mixed race, possibly Asian, around 5 ft 6 tall and of slim build.
He told his victim he was 17 before carrying out the horrendous attack.
His hair is described as swept back and he is also said to have an earring in his left ear and a slit in his eyebrow.
The victim was playing ball with her friend in the waters before she was dragged further out to sea and raped.
In a statement read by an actor on Crimewatch Live, the 15-year-old girl said: “It’s really changed me.
“I can’t face going out. I just feel frightened and vulnerable.
“I’m so scared and worried people will judge me for what happened.
“I didn’t ask for this, I tried to stop him but I couldn’t.”
The reconstruction, in which actors showed how the victim’s account unfolded, also included information about how the attacker approached the girl.
When the girl’s ball landed near a man and she asked for it back, he said no. Eventually he gave it to her but he dragged her out into deeper water.
The victim’s account added: “Before I could leave him he started to touch my arm and said come with me.
“At the same time another man was making my friend uncomfortable in the water so she decided to get out of the sea.
“I was alone now and the guy started pulling me out to deeper water and I couldn’t feel my feet on the seafloor.
“It’s then he started touching me and I was telling him no and to get out off me.
“No one could see what was happening.
“That’s when he raped me.”
DI Wayne Seymour said: “She’s very distraught and upset at what happened to her.
“She’s very, very brave coming forward to talk to us.”
The victim and her friend are said to have been sat by the pink elephant amusement ride, just left of Bournemouth Pier.
The attack itself took place just out to sea not far from this point on the beach.
DI Wayne Seymour also said: “It was one of the hottest days of the year, the beach that afternoon was absolutely packed, there were thousands of people there.”
Police are hoping information from the public could help develop the case.