Beate Arnestad, director of “Silenced Voices,” and Sonali Samarasinghe, one of the film’s subjects, discuss the film, which tells the story of Sri Lankan journalist Lasantha Wickrematunge, who was gunned down by eight men in broad daylight in Colombo. His wife, Sonali Samarasinghe, was forced to leave the country by the government. Sri Lanka is one of the most dangerous countries in the world for journalists. According to official sources, nearly 25 journalists have been killed there since 1992, at least 10 of whom were targeted by suspected government or opposition Tamil Tiger forces. “Silenced Voices,” will be shown as part of the Human Rights Watch Film Festival at Film Society of Lincoln Center’s Walter Reade Theater.