Brazilian authorities said Thursday that traces of blood were found in the boat of a man suspected to be linked to the disappearance of a British journalist and a Brazilian Indigenous specialist in the Amazon rainforest. Dom Phillips, a longtime contributor to The Guardian, and his friend Bruno Pereira, a Brazilian advocate for Indigenous groups, were last seen Sunday after receiving a threat from a group of illegal fishermen. With international concern mounting, Brazil said Wednesday that authorities had detained a suspect identified as “Pelado” in the case. The next day, police announced that “traces of blood were found on the boat” of a man named Amarildo da Costa de Oliveira, according to AFP. Samples have been taken and sent for expert analysis. Outside the Brazilian Embassy in London on Thursday, a vigil for Phillips and Pereira was held. “We want a persistent, deep, and open investigation,” said the journalist’s sister, Sian Phillips, in a statement at the gathering, adding that Phillips’ family wanted the U.K. government to pressure Brazil to step up the search.