DHS to monitor Secret Service probe WASIHINGTON, D.C., May 1 (UPI) -- The acting inspector general of the U.S. Department of Homeland Security says he will monitor the Secret Service's investigation of the prostitution scandal. Charles K. Edwards, in a message Monday to Congress, said his office decided the Secret Service was best qualified to investigate allegations of hard partying by agents sent to Cartagena, Colombia, to prepare for President Barack Obama's arrival, The Washington Post reported. He described the agency and its director, Mark Sullivan, as "completely transparent and forthcoming." Edwards said his office will conduct its own investigation of the Secret Service response, including disciplinary measures taken against agents for misconduct. Sen. Susan Collins, R-Maine, who has been calling for an independent investigation, welcomed his message and said "it is difficult for an organization to investigate and reform itself."