The founder and chairman of Blackwater USA, the private security contractor, has been told to appear next month before the House Oversight and Government Reform Committee. In a letter today to Blackwater chairman Erik Prince, Rep. Henry Waxman, D-Calif., said the hearing would concentrate on "the mission and performance of Blackwater USA and its affiliated companies in Iraq and Afghanistan." Blackwater’s role in providing security for the State Department in Iraq has been the focus of intense scrutiny this week after a firefight in Baghdad left as many as 20 civilians dead, allegedly killed by Blackwater guards. THE BLOTTER RECOMMENDS Blotter Despite Repeated Incidents, Blackwater, Others ‘Rarely’ Investigated Blotter Contractor Rules in Iraq: Fire Only ‘Aimed Shots Blotter Blackwater Scrutinized in Congressional Hearing The incident, which is now under investigation by both Iraq and the United States, is not the first time Blackwater has been accused of shooting Iraqi civilians. In his letter, Waxman touched on that performance record. "Another question will be whether the specific conduct of your company has advanced or impeded U.S. efforts," he wrote. Click Here for Full Blotter Coverage. Blackwater says its employees "heroically defended" the U.S. officials they were assigned to protect. As for Prince’s requested appearance before the congressional committee, Blackwater did not immediately respond to a request for comment. Next month’s hearing will not be the first time Blackwater has been the subject of a congressional hearing. This past February, families of the four contractors killed in a ghastly 2004 ambush in Fallujah testified before Waxman’s committee on how they believed Blackwater tried to cover up what led to that tragedy. The families told Congress they had discovered their men were sent out by Blackwater in unarmored cars, without automatic weapons, no maps and no tail-gunner to provide back-up as had been promised. Blackwater’s general counsel told the committee the security contractor didn’t cut any corners in providing for its workers and said Blackwater had met its obligation to equip the men in Fallujah adequately on the day of the ambush. "They just let him out there to die; they did not provide anything for him," Donna Zovko, the mother of one of the murdered contractors, said. Her son, Tom Zovko, reached earlier this week, had a similar sentiment for Blackwater when asked for his thoughts on the most recent incident in Baghdad. There is "absolutely no one that this company has to be accountable for," he told ABC News. They always "have a type of golden parachute to get out of it." The families of the slain contractors are currently involved in a lawsuit against Blackwater that has been tied up in "legal limbo for three years." Blackwater, which filed a counter lawsuit, maintains the men all knew the risks when they signed on to go to Iraq. "We’re not giving up," Zovko said of the suit. "We were wronged; our family members were wronged by people they were trying to help and that they trusted and for what?" Click Here to Register to Receive Blotter Alerts.