The Mexican drug runner whose testimony sent two Border Patrol agents to prison for shooting him in the buttocks brought drugs into the United States more than once, thereby diminishing his credibility as a witness in the investigation, according to a California congressman.

Rep. Dana Rohrabacher, R-Calif., presented new evidence in a Capitol Hill press conference Wednesday that revealed what he says was U.S. Attorney Johnny Sutton's deliberate attempt to mislead the public about Osbaldo Aldrete-Davila's involvement in the transport of a second load of drugs in October 2005.

Aldrete-Davila testified before a jury that former Border Patrol Agents Jose Compean and Ignacio Ramos shot him in February 2005 as he tried to run away from them near the U.S.-Mexico border in Texas. He was given immunity from prosecution in March 2005 for his cooperation in that investigation and subsequent trial, which culminated last year.

The Mexican was smuggling more than 700 pounds of marijuana into the United States at the time. Compean and Ramos were convicted last year and are serving 11 and 12 years, respectively, in separate federal prisons for the non-fatal shooting.

But the Drug Enforcement Agency found that Aldrete-Davila brought in another vanload of drugs into the United States while he waited to testify against the agents. Some reports say he stashed up to 750 pounds of marijuana at a house in Clint, Texas.

Rohrabacher said Sutton knowingly presented a false picture of the primary witness in the case.

"The U.S. Attorney's Office presented to the jury and presented to the public as if this guy Davila was a benign, hapless Mexican man who had just been recruited to drive a truck in order to raise money for medical expenses for his mother," Rohrabacher told FOXNews.com.

"Had the jury known that there were indications that he was a professional and he lied to his handlers even after they had granted him immunity for the first time, his testimony would have been worthless and it also suggests that he was more likely to have been carrying a weapon."

One of the border agents claimed they may have seen a weapon in Aldrete-Davila's hand during the incident. But the prosecutor said there was no evidence that he had a gun.

Aldrete-Davila was given immunity by the U.S. government and also received a border crossing card to come to and from Mexico to get free medical care in the United States for a bullet lodged in his body. Rohrabacher's office said it's unsure how many times Aldrete-Davila crossed the border during this time.

But the congressman says evidence has emerged that Sutton's office was notified by the DEA of Aldrete-Davila's direct involvement in the second offense but that it was ignored.

"The second offense goes just to the heart of the credibility of the Justice Department's primary witness against Compean and Ramos," Rohrabacher told FOXNews.com.

The documents Rohrabacher has is the report of investigation completed by the DEA.

"Our purpose here is not to endanger any agents" or reveal any information that may hurt the government's case, the congressman's spokeswoman, Tara Setmayer, told FOXNews.com on Wednesday. "But we do want people to understand we are in possession of documents that support the reports about Davila's involvement in a second drug-smuggling incident."

The DEA directed calls regarding what's known as the 'October load' investigation to Sutton, who represents the Western District of Texas. A prosecutor under Sutton handled the Compean-Ramos case.

"We cannot comment about matters that are under seal or ongoing investigations. This office will pursue criminal charges where there is prosecutable criminal activity and competent evidence to prove it," Sutton said in a statement.

"We have clearly stated that the immunity necessarily afforded to Aldrete-Davila in the investigation and trial of Ramos and Compean for the Feb. 17 incident would not extend to any subsequent or future criminal activity that may be alleged. It is truly unfortunate that some members of Congress have inaccurately implied that such immunity would be extended beyond the scope of this trial."

Some lawmakers in Congress, as well as Border Patrol activist groups, claim Sutton failed to prosecute the "real" criminal in the matter — the drug runner — and instead went after two Border Patrol agents just doing their jobs. Sutton, for his part, has argued that the law clearly states the mandatory sentences for such a shooting, and that there is no exemption for law enforcement. He has acknowledged to FOXNews.com, however, that 11 and 12 years in prison for such a crime may be extreme.

Champions of Ramos and Compean have asked President Bush to pardon the two agents, but to no avail.

A Justice Department lawyer on Wednesday told FOXNews.com that so far, the agency had not received any petition for clemency for either of the agents.

But in order to be eligible for a pardon approved by the Justice Department — which makes pardon recommendations to the president — five years must have elapsed from the day an individual was released from prison. Commutation is a shortening of one's sentence, but in order to be eligible for that, the person serving the sentence cannot be legally challenging his case.

However, the president can also make either decision on his own, regardless of the Justice recommendation.

Friends of the Border Patrol on Wednesday called for the firing of Sutton, along with other assistant U.S. attorneys who helped prosecute Compean and Ramos for what it calls "the malicious prosecution" of the two ex-agents and for "hiding key evidence from and lying to the American people, as well as harboring, aiding and providing comfort to a known drug smuggler, Osbaldo Aldrete-Davila, who illegally entered the U.S. from Mexico, assaulted Agent Compean, brandished a firearm towards two federal agents, resisted arrest and transported narcotics across international boundaries on multiple occasions."

The prosecution in the case says Aldrete-Davila did not have a gun, even though at least one of the agents thought he saw what could have been a weapon in his hand at the time of the shooting.

Friends of the Border Patrol also called for the resignation of Judge Kathleen Cardone, who it says "did everything possible to aid the prosecution in this witch-hunt, including sealing evidence and testimony that clearly would have damaged the credibility of the government's case and their alleged 'victim.'"