Special prosecutor Robert Mueller zeroed in on President Donald Trump’s business dealings with Deutsche Bank AG as his investigation into alleged Russian meddling in U.S. elections widens. Mueller issued a subpoena to Germany’s largest lender several weeks ago, forcing the bank to submit documents on its relationship with Trump and his family, according to a person briefed on the matter, who asked not to be identified because the action has not been announced. “Deutsche Bank always cooperates with investigating authorities in all countries,” the lender said in a statement to Bloomberg Tuesday, declining to provide additional information.