The investigation into Burr's transactions, first reported by CNN, is in its "early stages" and is in coordination with the Securities and Exchange Commission, according to sources.
Burr, who serves as chairman of the Senate Intelligence Committee, has adamantly denied any impropriety surrounding his sale of up to $1.7 million in stocks on Feb. 13, many in key industries hit hardest after the market's drop from novel coronavirus.
Several days later, the Dow Jones Industrial Average began an 11,000-point drop, although it has since rebounded somewhat.
Alice Fisher, a white collar defense attorney who is representing Burr, defended his trading activity in a statement to ABC News saying it was "based on public information."
"When this issue arose, Senator Burr immediately asked the Senate Ethics Committee to conduct a complete review, and he will cooperate with that review as well as any other appropriate inquiry," Fisher said. "Senator Burr welcomes a thorough review of the facts in this matter, which will establish that his actions were appropriate.”
The Justice Department and SEC declined to comment on the matter when reached by ABC News.
It is not clear whether the probe of Burr's activities extends to stock sell-offs around that same period by some of Burr's fellow lawmakers, including Sen. Kelly Loeffler, R-Ga., Sen. Dianne Feinstein, D-Calif., and Sen. Jim Inhofe, R-Okla.
All have denied that their stock activity had any connections to briefings that were provided to lawmakers at the time that had underscored the severity of the coronavirus and its potentially devastating ramifications for the U.S. economy and public health system.