During the 1990s, as a correspondent for the Globe and Mail, Vincent wrote several articles and a book, (See no evil) about the Abílio dos Santos Diniz kidnapping case in Brazil. Two young Canadians, David Spencer and Christine Lamont, had been convicted of Diniz's 1989 political kidnapping and confinement and sentenced to 28 years each in Brazilian prisons.

Vincent's writing was highly critical of Canadian media and their assumption that Lamont and Spencer must be innocent, attributing those assumptions to prejudices about Brazil. These writings brought Vincent a large amount of open hostility from the Canadian journalism establishment. However, a fellow investigative journalist, Caroline Mallan of the Toronto Star, also found strong evidence of Lamont's and Spencer's guilt, which she detailed in her own book Wrong time, wrong place?. In 1996, Lamont confessed that she and Spencer had participated in the kidnappings.

For her work on the Lamont/Spencer case, Vincent received the Canadian Association of Journalists' Award for excellence in investigative journalism and a Southam Fellowship.