VILNIUS (Reuters) -Lithuanian police said on Wednesday they had launched an investigation into an assault on Leonid Volkov, the long-time aide to late Russian opposition leader Alexei Navalny, after he was attacked outside his home in Vilnius. Volkov was attacked on Tuesday with tear gas and a hammer, suffering among other things a broken arm, a bruise to his forehead and a leg wound, former Navalny spokesperson Kira Yarmysh said. Volkov said in a Telegram post he was back home from hospital on Wednesday after receiving treatment, adding he had been hit about 15 times on his leg with a hammer.