Brit Matthew Gibbard, 50, was shot dead on Saturday morning outside the £350-a-night five star Faena Art Hotel in Buenos Aires, Argentina.
His stepson Stefan Zone, 28, was last night fighting for his life in hospital after also being fired at by the robbers.
Gibbard was fatally shot in the chest, and his son seriously injured in the horrific ambush moments after landing in Buenos Aires.
The two attackers had followed the six-strong British family by motorbike after marking their minibus when it left Ezeiza Airport.
Cops said that upon arriving at the exclusive, luxury five-star hotel, the men were attacked by gun-wielding motorcycle robbers in the Puerto Madero district of the capital.
Police said the robbers, who had been circling the area, also had a support vehicle nearby during their 11am ambush.
Mr Gibbard is the director of retirement homes firm Tingdene, which last year posted a turnover of £20million.
He is married to Suzanne, 52, and they live in a huge gates property in Lowick, a picture postcard village in Kettering, Northamptonshire.
Becky Miles, who works in the local pub the Snooty Fox, burst into tears over the tragedy and paid tribute to Mr Gibbard.
She told The Sun: “It’s absolutely terrible, they are lovely people. They were regulars in the pub.
“Matt was such a beautiful, beautiful human being and a true gentleman.
“He did so much for the village and even put the firework display on himself
“They are a very successful family and very popular in the village.”
Investigators at the National Prefecture have asked local cops and the Airport Security Police for details of the holidaymakers’ exact route to the hotel.
They believe the robbers had “marked” the family upon arrival at the international airport and that they followed their vehicle to launch a surprise attack as soon as they got out.
CCTV footage shows their minibus pull up to the hotel entrance, and a man help them take their luggage from the boot.
But suddenly all hell breaks loose and people are seen scrambling for cover from the vehicle.
The video, published by Argentina’s Perfil newspaper, shows the pair fighting with the robbers on the street until one thug pulls out a gun and shoots one of the men, who falls to the ground.
The other man tries to intervene and he too is shot, before the assailants flee the scene. Witnesses said at least five shots were fired.
Other surveillance footage appears to show three people, believed to be members of the family, fighting off the two attackers.
As the horrendous clip ends one man is seen lying on the floor apparently in agony.