U.S. border security officials learned of intelligence about the alleged extremist links of the suspect in the Christmas Day airline bombing attempt as he was en route to Detroit and had decided to question him when he landed, officials said in new disclosures today.

The new information shows that border enforcement officials came across important clues about the suspect despite previous intelligence failures that were criticized by President Obama this week.

If the intelligence had been discovered sooner, it could have resulted in the interrogation and search of Umar Farouk Abdulmutallab before he boarded the Amsterdam-to-Detroit flight, senior law enforcement officials said.

“The people in Detroit were prepared to look at him in secondary inspection,” said a senior law enforcement official who requested anonymity because the investigation is ongoing. “The decision had been made. The . . . database had picked up the State Department concern about this guy, that this guy may have been involved with extremist elements in Yemen. . . . They could have made a decision on whether to stop him from getting on the plane.”

Nonetheless, the revelations underscore the complexity of the intelligence and passenger screening systems that are the subject of comprehensive reviews to be revealed by the administration Thursday.

Even if U.S. border enforcement officials had learned of the Nigerian’s alleged extremist links in time, it is not clear the intelligence was strong enough to cause Dutch officials to search him or block him from flying, officials said. The threshold for requiring a foreign visitor to undergo special scrutiny upon arrival in the United States is considerably lower than criteria for preventing him from getting on the plane overseas, according to current and former law enforcement officials. That is why border enforcement officials rely heavily on terrorism watch lists, officials said.

“The public isn’t aware how many people are allowed to travel through the U.S. who are linked, who intersect with bad guys or alleged bad guys,” a national security official said. “It makes sense from an intelligence perspective. If they are not considered dangerous, it provides intelligence on where they go, who they meet with.”

Moreover, the window for identifying a passenger as a potential threat before boarding is limited, according to a senior homeland security official. Although U.S. border enforcement officials have access to passenger data based on reservation lists and use them for preliminary assessments, the in-depth vetting by Customs and Border Protection only begins once the flight manifest has been generated, just a few hours before takeoff, and focuses on potential actions to take at the U.S. border, the official said.

As a result, the intelligence about Abdulmutallab was discovered in a database by Customs and Border Protection inspectors based at the National Targeting Center in Washington once the plane was airborne, the other law enforcement officials said. The administration’s review of screening now underway includes an effort to make more information accessible to U.S.inspectors further in advance of flights, the senior law enforcement official said.

Customs and Border Protection spokesmen declined to comment because the investigation is still open.

In Detroit today, federal prosecutors filed a six-count indictment charging Abdulmutallab, 23, for his alleged role in the attempted bombing of Northwest Airlines Flight 253. The Nigerian already had been charged in a criminal complaint, and the indictment accuses him of placing a destructive device on an aircraft, attempted use of a weapon of mass destruction and other charges that carry a penalty of up to life in prison.

“This investigation is fast-paced, global and ongoing, and it has already yielded valuable intelligence that we will follow wherever it leads,” Atty. Gen. Eric H. Holder Jr. said today. “Anyone we find responsible for this alleged attack will be brought to justice using every tool -- military or judicial -- available to our government.”

Abdulmutallab has provided valuable information to the FBI and federal prosecutors about his dealings with extremists in Yemen, where he was allegedly trained and outfitted with the explosive device that he concealed in his underwear during the trip that began in Ghana, according to U.S. law enforcement officials. Abdulmutallab has told interrogators that the plot involved meetings in Yemen with Anwar al Awlaki, an American-born Yemeni cleric suspected of involvement with Al Qaeda. In addition, communications intercepts detected discussions about Awlaki’s role in a suspected plot involving a Nigerian, U.S. officials have said.

The investigation has also uncovered communications between Abdulmutallab and Awlaki, a U.S. anti-terrorism official said today.

“He was definitely in communication with Awlaki,” said the official. “That’s been documented.”

Justice Department officials declined to comment on whether Abdulmutallab’s cooperation could result in a reduced sentence. But officials familiar with the case have said a plea deal could short-circuit the debate over his being charged in a civilian court.

Some Republican lawmakers and independent Sen. Joe Lieberman of Connecticut, chairman of the Homeland Security Committee, have criticized the Obama administration for that decision, saying he should be interrogated and charged as an enemy combatant, without the right to counsel.

Times staff writers Josh Meyer and Christi Parsons contributed to this article.