Pop star Rihanna has paid tribute to a teenage superfan in Brazil who was murdered in a triple homicide on Saturday (01Feb14). James Sobral Valencia, aka Thiago, was stabbed to death at his mother's home in the city of Aracaju. The 15 year old's mum Vanessa and his nine-year-old brother, Osvaldo, were also murdered. Local fans alerted Rihanna to the tragic news via Twitter.com, and the Umbrella hitmaker rallied her 33.9 million followers to offer their support to the youngster's grieving relatives. In a tweet on Sunday morning (02Feb14), she wrote, "R.I.P. To one of our fallen soldiers, brutally murdered yesterday in Brazil! 14 year old (sic) Thiago, will forever be in our hearts!". She subsequently added, "Just learned that Thiago's mother and sibling were also murder victims in the horrible and tragic turn of events! Dear God! Let's send our support to his family and friends during this difficult time guys! #RIPThiago". Rihanna also remembered the devotee by sharing a photo of him on her profile page. Brazilian police are currently searching for Valencia's stepfather, who is believed to be responsible for the murders.