Pentagon investigators are also probing claims of personal relationships between Army officials and contractor firms tied to the Russian program, according to Reuters.
The company has already been the focus of intense scrutiny by certain members of Congress, led by Sen. John Cornyn (R-Texas).
"The prospect that American taxpayers have been made into unwitting victims of corruption demands special scrutiny," Cornyn spokesman Drew Brandewie said Thursday.
The ongoing Pentagon investigation into the Army's contracting practices "raises very serious questions about the Army’s entire Mi-17 program," he said in a statement to The Hill.
Cornyn has criticized the Pentagon's relationship with Rosoboronexport, given the company's past arms deals with Syrian President Bashar Assad.
Last June, the Texas Republican blocked the nomination of the Army's acquisition chief, Heidi Shyu, over concerns about the company's involvement in the Mi-17 deal with the Defense Department.
Aside from helping arm the Assad regime during its ongoing civil war with anti-government rebels in the country, U.S. intelligence claims Rosoboronexport is also supplying Tehran with critical components to support its current long-range missile development program.
The Pentagon has defended its tied with the Russian weapons maker, claiming the company's supply of Mi-17 helicopters is critical to getting Afghan air forces up and running.
“The Mi-17 helicopter, from our vantage point, is about Afghanistan. It's about equipping the Afghan air force with what they need to ensure that they have the capabilities from an air standpoint to defend themselves,” Pentagon press secretary George Little said last June.