SAN FRANCISCO/NEW YORK (Reuters) – Federal authorities in San Francisco are probing U.S.-based Mirach Capital Group, two sources familiar with the situation told Reuters, amid allegations that the group gave a forged bank letter to Indian conglomerate Sahara as part of financing negotiations. Sahara had sought to borrow more than $1 billion from Mirach to help bail its chairman, Subrata Roy, out of jail in New Delhi. The Indian company negotiated for funds with Mirach, a group set up by former broker Saransh Sharma, who lives in Northern California.