Surfing world mourns slain Brazilian

Ricardo Dos Santos surfing during the Billabong Pipe Masters in North Shore, Hawai. Photo / Getty

Australia's three-time world champion Mick Fanning is grieving the loss of pro surfer Ricardo dos Santos, who has died after being shot three times outside his beachside home in Brazil.

"So sad to hear the news of Ricardo Dos Santos passing. Prayers and thoughts to his family," he posted on Instagram. "Loved big tubes and rode them extremely well. May he Rest In Peace."

Santos was shot outside his home in the country's south, allegedly by a police officer.

The 24-year-old was attacked on Tuesday (AEDT) near the city of Florianopolis, when he went outside to confront an off-duty policeman and the officer's younger brother.

Police, however, collected conflicting reports about whether dos Santos asked the men to leave when he spotted them doing drugs or whether he was shot while discussing a car they had parked at his property.

The surfing world has rallied online to pay their respects to the daring tuberider, who underwent four surgeries at the Sao Jose Regional Hospital before dying on Wednesday.

"Ricardito, you did not deserve this... Why did this happen to a good person? I don't understand," Gabriel Medina, the world surfing champion and a friend of dos Santos, posted on Instagram.

He wrote that dos Santos was "always helping others, smiling from ear to ear every day ... God comfort his family".

American 11-time world champion Kelly Slater noticed a floating memorial ceremony taking place for dos Santos in Hawaii on Wednesday.

"Beautiful morning but I was horrified to realise everyone was paddling out to Pipe to form a circle in remembrance of my friend," he posted on Instagram. "Our small community has lost another way too soon."

Slater said dos Santos was one of the great barrel riders of his short time, which Slater learnt "the hard way" at the 2012 Billabong Pro in Tahiti.

Dos Santos won the Andy Irons Award for Most Committed Performance at the event on the notorious Teahupo'o reef break, and was awarded the Wave Of The Winter in 2012-13 for a barrel he caught at Hawaii's Pipeline.

Slater said it was "truly a senseless loss of life".

"It unfortunately brings to light the number of murders yearly in Brasil, officially documented at over 50,000 with many thousands more going unreported," he wrote. "Lack of education, poverty and drugs don't make for a good mix and make life challenging in this country, one of the most beautiful and scariest places I've been.

"Condolences to Ricardo's friends and family around the world."

-AAP