Dish Network warns of SoftBank's ties to bribery

During that time, UTSI illegally bribed Chinese officials for telecommunications contracts, according to the Justice Department. UTSI agreed to pay a $1.5 million fine to settle the Justice Department charges in 2009.

According to the settlement, UTSI admitted that it paid for vacations for Chinese officials and improperly accounted for them as "training" trips.

"The affiliation between SoftBank and UTSI seems to have been close," Dish argued in its filing, noting that SoftBank was also the largest shareholder of UTSI.

"Dish believes that this information is relevant to the public interest analysis of the proposed transaction, and that it is incumbent upon the proposed transferee SoftBank to provide a full explanation of these matters," Dish wrote.

SoftBank did not respond to a request for comment.