Washington (CNN) -- When FBI agents arrested a Saudi student in Texas on a terror-related charge last week, authorities praised two companies that, it appeared, triggered the investigation by reporting the man's suspicious attempt to purchase a hazardous chemical.
Now, the Department of Homeland Security says it had information that raised suspicions about Khalid Ali-M Aldawsari even before the two companies reported their suspicions.
In testimony before the House Homeland Security Committee, Homeland Security Secretary Janet Napolitano said Thursday that Immigration and Customs Enforcement (ICE) officials received a "suspicious activity report" concerning the student's banking activity before tips from a chemical company and shipping company came in.
ICE "notified the FBI," Napolitano said. "The FBI and ICE then pursued an investigation and of course that led ultimately to the arrest of the individual involved," Napolitano said.
This is a "good news story," Napolitano said, noting the department's efforts to routinely monitor the suspicious financial activities of foreign students.
The FBI's detailed 13-page affidavit for Aldawsari seeking his arrest makes no mention of the suspicious bank transactions; however, law enforcement does not always include every piece of information about an investigation in initial filings.
Committee Chairman Rep. Peter King, R-New York, asked whether whether there was "sufficient follow through" on the ICE report, and if it triggered a sufficient investigation.
"My understanding was if he (Aldawsari) had gotten the Phenol (chemical), the bomb would have been ready to go. So even though ICE had made this discovery, still he was in a position to possibly launch an attack," King said.
Napolitano said DHS is giving credit to the chemical and shipping companies and others. "We give credit there. We give credit to ICE. They all ultimately were converging on one individual," Napolitano said.
The FBI would not comment on whether it had received a report about Aldawsari's banking activities from ICE. A Justice Department spokesman said the department "cannot comment beyond what is in the criminal complaint at this time." The Department of Homeland Security also refused to elaborate on the secretary's comments.
Aldawsari, 20, is charged with one count of attempted use of a weapon of mass destruction.
The Saudi national living in Lubbock, Texas, was arrested after he allegedly acquired chemicals for a bomb and researched several possible targets, including the Dallas home of former President George W. Bush, nuclear power plants, hydroelectric dams and the homes of former military personnel who had been stationed at the Abu Ghraib prison, federal authorities said.
Officials said Aldawsari was lawfully admitted into the United States in 2008 on a student visa, studied chemical engineering at Texas Tech, and currently is enrolled at South Plains College near Lubbock.
According to court records, Aldawsari had been conducting online research on how to construct a chemical IED, or improvised explosive device. He also had "acquired or taken a substantial step toward acquiring most of the ingredients and equipment" needed, according to an affidavit filed in U.S. District Court in Texas.
In a personal journal found in Aldawsari's apartment home, the writer explained that the events of September 11, 2001, had produced a "big change" in his thinking, that he had been inspired by the speeches of Osama bin Laden, and had excelled in high school in order to take advantage of scholarship opportunities, offered by Saudi companies, to get to the United States. He stated in his diary he had been planing to commit a terrorist attack in the United States for years, the affidavit says.
CNN's Carol Cratty and Jeanne Meserve contributed to this report.