An Islamic State fighter waves the group’s flag from inside a captured government fighter jet following the battle for the Tabqa air base in Raqqa, Syria. (AP)

The way federal prosecutors told it, Jesse Morton was an inspiration for terrorists across the world. Through his Revolution Muslim website, they said, the New York City man provided justification for violence in the name of Islam, encouraged followers to support Osama bin Laden and advocated attacks on the writers of “South Park” in retaliation for their depiction of the prophet Muhammad in a bear suit.

“Morton not only endangered the lives of innocent people,” prosecutors wrote, “but he also contributed to the destruction of the very freedoms on which our society is based.”

A federal judge in 2012 agreed that Morton deserved a harsh punishment, sentencing him to 11 1/2 years in prison. But less than three years later, the 37-year-old is out and being paid by the FBI, according to government records and an attorney who says Morton helped federal officials build a case against a client accused of trying to join the Islamic State.

Though police cooperators receiving sentencing breaks is hardly a novel practice, Morton’s release is unusual in that, at least when he pleaded guilty, federal authorities billed him as particularly malevolent.

“We may never know all of those who were inspired to engage in terrorism because of Revolution Muslim, but the string of recent terrorism cases with ties to Morton’s organization demonstrates the threat it posed to our national security,” then-U.S. Attorney Neil MacBride said in a statement at the time.

The exact details of Morton’s release remain murky. A person familiar with the case, who spoke on the condition of anonymity to discuss court matters that largely remain secret, said prosecutors sought to reduce his sentence because they believed he had been reformed and he had cooperated fully with investigators.

MacBride, who stepped down as U.S. attorney in late 2013 for a job in the private sector, said in a statement that he wasn’t aware that the government had pushed for Morton’s early release.

“I presume that they only did it because he offered substantial assistance to the FBI in other investigations,” MacBride said. He said that although reductions in such cases were uncommon, they had happened in federal court in the Eastern District of Virginia in 2006 for three defendants who attended terrorist training camps, then helped in other cases.

Muslim leaders have long criticized the FBI’s use of informants and its sometimes aggressive approach to keeping tabs on Islamic communities. Four American Muslims alleged in a recent lawsuit that their names were put on the no-fly list as part of a heavy-handed effort to coerce them to work on the FBI’s behalf. (That suit was dismissed late last year, but the men were taken off the no-fly list). The New York City Police Department agreed this year to settle lawsuits that alleged that Muslims were investigated and targeted for surveillance without good reason — agreeing to pay $2 million in attorney fees while admitting no wrongdoing.

Information about Morton’s release and work as an informant spilled into public view Jan. 27, when an attorney for a man in Woodbridge, Va., who was charged last month with helping a friend try to join the Islamic State identified Morton using an alias in open court.

The attorney, Ashraf Nubani, said a man named Younus Abdullah, who had ties to the Revolution Muslim website, was a government informant in the case against his client, Mahmoud Amin Mohamed Elhassan, 25. “Younus Abdullah” or “Younus Abdullah Muhammad” are aliases that Morton has long used.

Efforts to locate Morton, a father of two who has a master’s degree from Columbia University, were unsuccessful. The Bureau of Prisons website indicates that he was released in February 2015, and he appears to have announced it on the website islampolicy.com.

“While I am no doubt bewildered by the prospects of facing the currents of American society, labeled American Al-Qaeda, I do want to remain cognizant that this opportunity to be a freeman, a husband, a father, and citizen comes from Allah alone,” he wrote.

Morton did not return email and Facebook messages seeking comment. His father declined to comment, and his attorney and other family members did not respond to phone messages. The person familiar with the case noted that his release from prison was not tied directly to Elhassan’s case.

Morton pleaded guilty in 2012 to conspiring to solicit murder, making threatening communications and using the Internet to place others in fear. In announcing his plea, federal authorities said his website helped radicalize people across the world, and he had contact with some who had specific, violent plots in mind. For example, he worked with Zachary Chesser — an Oakton High School graduate who tried to join an al-Qaeda-linked terrorist group in Somalia — to promote attacks on the writers of “South Park,” according to his plea. He also was in touch with Rezwan Ferdaus, who admitted to plotting to attack the Pentagon and U.S. Capitol, and with Jose Pimentel, who was arrested in a plot to kill members of the U.S. military returning from active duty in Afghanistan.

Morton’s attorney at the time asserted that many of Morton’s postings, while potentially offensive, were not threatening or illegal. For his part, Morton apologized and noted that he could be “an asset in promoting peace once I am free.”

“I continue to participate enthusiastically and honestly during the debriefing process, and I can honestly tell you that I have reformed and that were you to let me go today, I would work diligently and with similar passion to correct the mistakes I have made,” he said, according to a transcript of his June 2012 sentencing hearing.

U.S. District Judge Liam O’Grady ultimately sentenced him to 11 1/2 years in prison. A sealed document appears in the case in June 2013, according to the court’s docket, but there was more activity — including a secret hearing — the following year.

Officials with the FBI and the U.S. attorney’s office in the Eastern District of Virginia declined to comment.

Federal agents arrested Elhassan and another man, Joseph Hassan Farrokh, 28, last month, charging Farrokh with trying to provide material support to terrorists and Elhassan with aiding that plot. They alleged that Farrokh intended to travel to Syria and join the Islamic State; he was arrested at Richmond International Airport, where his journey allegedly was supposed to begin.

Elhassan, federal authorities alleged, knew of Farrokh’s plot, gave him a ride to Richmond and lied to FBI agents who questioned him after Farrokh’s arrest. According to an affidavit in the case, federal agents knew about the men’s whereabouts because they were unknowingly working with three government informants to help facilitate the plot.

Farrokh, a U.S. citizen born in Pennsylvania, was recently married and has a baby on the way, authorities have said. Elhassan, who came to the United States from Sudan and has a green card, was attending Northern Virginia Community College and working intermittently as a cab driver before his arrest, family members and friends have said.

Morton, or Younus Abdullah, is described in the affidavit only as “CHS #3,” someone who had been convicted of criminal offenses and received a sentence reduction for his cooperation. He was paid more than $10,000 by the FBI, according to the affidavit.

When Nubani first invoked the name “Younus Abdullah” in federal court, Assistant U.S. Attorney Dennis Fitzpatrick quickly objected, saying Nubani’s assertion was “total speculation.” A judge struck the name from the record. Later in the hearing, Nubani referenced the Revolution Muslim site.

In a conversation later with a reporter, Nubani said his client was able to identify Morton, whom he knew as Younus Abdullah, as “CHS #3” because the law enforcement affidavit details their interactions.

The affidavit alleges Elhassan first introduced Farrokh to CHS #3, a man whom Elhassan believed to be someone who maintained connections with “individuals engaged in jihad outside the United States.” It alleges Farrokh asked for help getting to Syria, and Farrokh was soon set up with two other government informants, one of whom he believed to be an Islamic State facilitator.

Joe Flood, an attorney for Farrokh, declined to comment.

Nubani said that Elhassan knew Morton as someone who had been “oppressed by the government,” and that that is why he introduced him to Farrokh. He said he did not know the specifics of how Elhassan and Morton met. Nubani said Elhassan, like many other Muslims in the country, was caught up in a government-manufactured plot meant to convince the American public that the FBI was working to keep them safe.

In reality, Nubani said, the government’s informants “controlled every aspect” of the purported plot involving Elhassan and Farrokh.

“There was no danger to anyone, at any time,” he said.