MOSCOW (Reuters) - Russian authorities in the city of Nizhny Novgorod opened a preliminary investigation after the body of a woman with severe burns was discovered in the city centre, the local Investigative Committee said in a statement on Friday. Irina Slavina, a journalist, died after setting herself on fire in front of the local branch of the interior ministry in Nizhny Novgorod earlier on Friday, a day after her apartment was searched by police, according to local and social media.