(Adds more comment from SolarWinds) WASHINGTON, Feb 2 (Reuters) - Suspected Chinese hackers exploited a flaw in software made by SolarWinds Corp to help break into U.S. government computers last year, five people familiar with the matter told Reuters, marking a new twist in a sprawling cybersecurity breach that U.S. lawmakers have labeled a national security emergency. Two people briefed on the case said FBI investigators recently found that the National Finance Center, a federal payroll agency inside the U.S. Department of Agriculture, was among the affected organizations, raising fears that data on thousands of government employees may have been compromised.