Rio de Janeiro, February 11 (RHC) -- Brazilian President Dilma Rousseff condemned the violence against a cameraman who was declared brain dead after being injured when covering a protest against bus fare hikes in the city of Rio de Janeiro last week.

Santiago Andrade's tragedy was a "sad, revolting incident," Rousseff said on her Twitter account. "We cannot allow democratic protests to be tainted by those who have no respect for human lives."

"Freedom of protest is a fundamental principle of democracy and cannot be used to kill, injure and threaten human lives, nor destroy public or private property," added the president.

Rousseff said she had ordered the Federal Police to help the Rio police investigate the case, and Brazil's G1 news website reported later that the man believed responsible was temporarily detained.

Andrade, who worked for local TV station Bandeirantes, was struck on the head by a stray skyrocket during a protest Friday.

He underwent a surgery on the same day, but his condition was grave and he fell into a coma. Doctors declared Andrade brain dead late Monday morning.