RIO DE JANEIRO — The killing of a transgender woman who was beaten, tortured, shot and then bashed on the head with a big stone has horrified and transfixed Brazil, training attention on the violence and discrimination suffered by transgender people in South America’s most populous nation.

The victim, Dandara dos Santos, 42, was killed in Fortaleza, in the northeastern state of Ceará, on Feb. 15, but the case has gained international attention as a cellphone video documenting her abuse has circulated on YouTube and other social media.

The police in Brazil have arrested three teenagers and two men in connection with the torture and killing. Officers said that the video had helped them identify the suspects but that they were still looking for others.

“Every and any attack on life has my deepest repudiation,” the governor of Ceará, Camilo Santana, wrote in a Facebook post on Saturday.