The battle between Japan's SoftBank and Dish Network (NASDAQ: DISH) for control of Sprint Nextel (NYSE:S) is getting nastier, with Dish warning the FCC that it should take into account SoftBank's ties to UTStarcom, which settled bribery allegations in 2009 with the Department of Justice. The filing by Dish comes shortly after SoftBank CEO Masayoshi Son said his company will not raise its $20.1 billion offer for 70 percent of Sprint to compete with Dish's unsolicited $25.5 billion counterbid because he said SoftBank's offer is already superior. Son called Dish's offer "incomplete and illusory" and said Dish's offer "includes statements that are misleading." In a filing with the FCC, Dish pointed to recent media reports from TR Daily and Politico about the DOJ investigation into UTStarcom, known as UTSI.