The next wave of Al Qaeda recruits are born or educated right in the United States. Most are just old enough to remember 9/11, yet a decade a later they are turning their back on the United States.

The threat posed by this new generation of terrorists was underscored this week by the case of Khalid Aldawsari, a 20-year-old Saudi national who came to the United States legally in 2008 to attend college in Texas. Now he is accused of plotting to bomb a series of U.S. targets, including the Dallas home of former President George W. Bush.

What is striking about the Aldawsari case is that he wasn't arrested in an FBI sting operation. Law enforcement sources were quick to point out that a central tip came from a chemical supplier who said he was suspicious about the amount of phenol Aldawsari wanted to buy.

Authorities allege that Aldawsari was a “lone wolf,” not working with others and apparently not connected to or receiving direction from an overseas terrorist network.

The threat from so-called lone wolf operators was the subject of a recent intelligence assessment obtained by Fox News as part of an on-going investigation into the American born cleric Anwar al-Awlaki, who is said to be an operational planner for Al Qaeda’s affiliate in Yemen. The assessment, titled “Evolution of the Terrorist Threat to the United States,” clearly says the threat is more diversified than ever before.

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While there is no way to know how many lone wolf operators are inside the U.S., the threat has evolved since 9/11.

In simple terms, there are now three threat streams. The first originates in the tribal areas of Pakistan with the remaining Al Qaeda leadership, also known in intelligence circles as Al Qaeda core. U.S. officials says they are diminished by the CIA drone campaign, but they still try to launch large-scale attacks.

The second comes from Al Qaeda affiliates, like Awlaki’s group in Yemen. This is the group said to be behind the attempted Christmas Day underwear bomber, as well as the failed cargo jet bomb plot in October 2010.

And the third is the homegrown or self-radicalized operative.

“The United States now faces a diversified threat from a number of violent 'jihadist' groups that are aligned ideologically with, but not necessarily directed by al-Qa’ida (AQ) in Pakistan,” The internal DHS assessment says.

“These individuals identified with the ideas and goals of the global violent jihadist movement, but lacked direct guidance and instructions from the leadership from a formal terrorist network,” the assessment continued, referring to a half dozen recent lone wolf cases. “Given recent activity by Al Qaeda and its affiliates, we have to operate under the premise that other operatives are in the country and could advance plotting with little or no warning.”

In the Aldawsari case, court documents allege that he was inspired by Usama Bin Laden in the wake of 9/11 before he was a teenager. He allegedly wanted to create an Al Qaeda branch in the U.S.

As the case unfolds, more is likely to be revealed about his motivations and whether he, too, was inspired by the American cleric Awlaki, linked to more than a dozen cases in the U.S.

The new generation, especially those inspired by Awlaki’s brand of hate, often can be called digital jihadists -- Al Qaeda 2.0. They seek the radical message on the Web. They even find training. But most of all, they find like-minded individuals who reinforce their radical views through social networking sites. It gives them the courage to act.

The lone wolf scenario is seen by many counterterrorism officials as one of the most concerning. The larger the plot, the more individuals who are involved, the more likely it is to find a lead and unravel the operation.

If a suspect is not e-mailing or phoning anyone to develop the plot, it can be virtually impossible to thwart. In the Texas case, it is alleged that the suspect slipped up as he was gathering the remaining components to make IEDs.

Aldawsari pleaded not guilty on Friday. His lawyer, Rob Hobson, issued a statement Friday that reads in part:

“This is not Alice in Wonderland where the Queen said 'first the punishment then the trial.' This is America, where everyone is entitled to the presumption of innocence, due process, effective representation of counsel and a fair trial.

"I request that everyone take a step back and allow the legal proceedings to unfold in a timely and orderly fashion. The eyes of the world are on this case and the treatment of this accused person. This is a wonderful opportunity for us to show the world how truly fair our legal system is; even to those who are accused of trying to harm our country.”

Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security. Herridge joined FNC in 1996 as a London-based correspondent.