Jalil Aziz didn't kill anyone on behalf of the terrorist group ISIS.

The 21-year-old Harrisburg man did, however, use the internet to urge others to commit murder.

His worst crime, federal prosecutors say, was to retweet an ISIS "kill list" that urged the terror group's backers to kill 100 U.S. service people, preferably by beheading them in their own homes.

Judging from his tweeting, he found the idea of the murders amusing.

On Wednesday, two years after heavily-armed federal agents swooped down on his Fulton Street home, Aziz paid the price for his homicidal online activity.

U.S. Middle District Chief Judge Christopher C. Conner sentenced Aziz to 13.3 years in federal prison, to be followed by 12 years of probation with strict monitoring of Aziz's computer use. Conner also ordered Aziz to pay $6,635 in restitution to the people on the kill list who purchased security upgrades for their homes after Aziz retweeted it.

"This defendant's crime did not involve an individual victim. However, the defendant's actions constituted a serious crime against the United States," the judge said. "I find that at the present time this defendant represents a threat to the public."

Federal prosecutors had sought a 25-year prison term for Aziz. After the 3 1/2-hour sentencing hearing, U.S. Attorney David Freed stressed that, while Aziz won't spend 25 years behind bars, he will still be under close federal supervision for the next quarter-century.

The outcome for Aziz could have been much worse, fatal, in fact.

When Aziz, a U.S. citizen, was arrested in December 2015 - after a month of close surveillance by federal agents - ISIS ruled an extensive and brutal "caliphate" in Syria and Iraq. Its skewed justice system involved televised beheadings of ISIS opponents.

That bloody empire is just a bad memory now, buried, along with the corpses of thousands of ISIS fighters, under the rubble of ruined but recaptured cities.

Freed said he is convinced Aziz's arrest not only saved inestimable American lives, but also saved Aziz's own life by sparing him the fate of so many of ISIS's apostles.

During Wednesday's hearing, defense attorney Bernard Grimm sought clemency for Aziz, calling his client a lonely social misfit who grew up isolated by overbearing parents who rarely let him venture outside the home. He insisted that, emotionally, Aziz is "really nothing more than a baby" who is amenable to reform.

"Would Mr. Aziz raise a weapon and fire at another human being?" Grimm asked. "I'd bet my life savings that he wouldn't."

Aziz, who pleaded guilty to abetting terrorism, told Conner that, "I didn't hurt anyone." He said the praise he received from ISIS for helping to spew its propaganda "falsely gave me the belief that, for the first time in my life, I was important."

He said he realizes now that the hate he helped circulate on behalf of the radical Islamist group would not be endorsed by anyone's God. "There is nothing wrong down deep with who I really am," Aziz said.

Freed later called Aziz's statement "his first indication of any type of apology or remorse."

Aziz's brother and sister attested to Aziz's smothering home life that they said robbed him of friends and most human contact. His brother, Ibrahim, vowed to ensure his little brother gets the treatment he needs to rejoin society.

"I would be terrified if a neighbor of mine was accused of the crimes my brother admitted," Ibrahim said. He conceded that his brother's on-line activity was "ugly, disgusting and despicable," but added, "I can guarantee they were just talk."

Ibrahim berated ISIS as "sick individuals who have hijacked my religion."

As counterpoint to the defense arguments, prosecutor Robert J. Sander had counterterrorism agent Jeffrey Gruppo show Conner Aziz's pro-ISIS tweets and an array of items seized from Aziz's home.

Those included 100 rounds of military-grade rifle ammunition - which was bought by Aziz's father - that was found behind a dryer in the laundry room next to Aziz's bedroom. A "military-style" backpack removed from Aziz's closed contained, among other things, a kitchen knife with a cloth-wrapped broken handle and several 30-round rifle magazines.

"I can get that backpack over the internet?" Grimm asked on cross-examination.

Yes, Gruppo replied. He agreed with Grim that having, or even wearing such a pack in public, isn't illegal.

Sander insisted that Aziz was amassing items for a domestic terror attack. He flashed one of Aziz's online photos on the computer screen. It showed weapons and a masked ISIS fighter holding the group's flag and aiming a machine-gun. The caption Aziz put on the entry was, "Life goal."

"His repeated threats were not the idle warnings of an internet warrior," the prosecutor said. He cited a psychological evaluation that concluded Aziz has poor impulse control and limited judgment and could be susceptible to further radicalization in the future.

Conner spent at least 20 minutes explaining the rationale for the penalty he chose.

He called Aziz's acts "atrocious," and said they "specifically jeopardized more than 100 U.S. servicemen and women and broadly endangered the public at large."

Still, Conner said Aziz's punishment must be in tune with that imposed on others who aided terrorists without committing violence themselves. The judge noted, for example, that the man who hacked the information used to compile the ISIS kill list that Aziz retweeted received a 15-year federal prison term.

Citing the psych report, Conner found that Aziz still represents a threat to the public. And he acknowledged that, if treatment doesn't succeed, Aziz could become a dangerous radical again.

"I hope I am incorrect in that respect," the judge said.