(Bloomberg) The U.S. Securities and Exchange Commission, responding to a watchdog's criticism that it bungled fraud claims against R. Allen Stanford, has strengthened its investigations and is pursuing several people linked to the Texas-based executive, agency officials told lawmakers.

The SEC has added investigators and improved handling of tips after Inspector General H. David Kotz faulted the agency's probe of Stanford, who is facing trial for an alleged $7 billion fraud, Enforcement Director Robert Khuzami said today in remarks prepared for a Senate Banking Committee hearing. The agency is "also vigorously pursuing its case against Stanford and the others charged in this massive Ponzi scheme," Khuzami said.

"The scope and egregiousness of Stanford's conduct and the resulting injury to investors underscores that it is essential for us to push forward with our efforts to hold the wrongdoers accountable and seek maximum investor recovery," Khuzami said.

Khuzami, Carlo di Florio, head of the SEC's Office of Compliance Inspections and Examinations, and Rose Romero, director of the agency's regional office in Fort Worth, Texas, were called to testify on progress in implementing changes Kotz proposed in an April report on the Stanford case. Kotz said the SEC failed to conduct a meaningful probe of Houston-based Stanford Financial Group Co. until 2005 even though examiners suspected he was running a Ponzi scheme eight years earlier.

The SEC sued Stanford, 60, in February 2009, claiming his Antigua-based firm, Stanford International Bank Ltd, defrauded investors by selling billions of dollars in bogus certificates of deposit. He is jailed in Houston while awaiting trial on related criminal charges, and at least three of his top executives are facing related claims.

Khuzami said the enforcement unit has addressed all of Kotz's recommendations, which included steps to ensure potential harm to investors is weighed when deciding whether to pursue a case and grading employees based on their willingness to take on difficult probes that are important to investor protection.