MOSCOW - Authorities have arrested a man from Chechnya on suspicion of involvement in the slaying of Paul Klebnikov, the American editor of Forbes magazine's Russia edition who was gunned down outside his Moscow office in July, according to a media report. A Moscow court sanctioned the arrest of Musa Vakhayev, 40, a resident of the Chechen town of Urus-Martan, the Interfax news agency reported Friday, citing an unnamed source in the court. Authorities must charge Vakhayev within 10 days or release him, according to the report. The killing of Klebnikov, 41, compounded concerns about the safety of journalists in...