NEW YORK (AP) — An appeals court affirmed a 55-year prison term Tuesday for a member of the MS-13 gang who organized the killings of four teenagers in a Long Island park when he was 15 — but it also expressed regret that the end of parole for federal prisoners means he won't have incentive to reform.

A panel of the 2nd U.S. Circuit Court of Appeals ruled that the prosecution of Josue Portillo, now 19, is a “classic illustration of the unfortunate consequences” of a decision by Congress that eliminated parole for federal prisoners sentenced in or after 1987.

The ruling, written by Judge Jon O. Newman, said the intent of Congress to end disparities in sentences and to send a message to the public that prisoners will serve nearly all of their sentences was not achieved, in part because the public gets a muddled message since most state courts still offer parole.

The 2nd Circuit said parole might motivate Portillo to obey prison rules, obtain education, participate in rehabilitative programs and mature to a point where he could rejoin society.

An email message seeking comment was sent to Portillo’s lawyer.

Portillo, facing deportation to El Salvador when his sentence ends, pleaded guilty in the April 2017 massacre after planning it for weeks because he was offended that a youth who was not an MS-13 member had flashed the gang's symbol and acted as if he was, prosecutors said.

In a presentencing memorandum, prosecutors said Portillo arranged for two female friends of the gang to lure him to a Central Islip park where over a dozen MS-13 members waited to attack the teenager and four members of a rival gang he had brought with him.

The teenager who was originally targeted escaped over a fence, but the others were killed by MS-13 gang members wielding knives, machetes, an ax and clubs made out of tree limbs, prosecutors wrote.

The appeals court acknowledged that the crime was “especially heinous” and that Portillo actively participated in the killings and planned the crime in retaliation for a petty grievance. But it also said the case “illustrates the unfortunate consequences of eliminating parole.”

Long Island has been hit especially hard by the presence of MS-13, with dozens of murders since January 2016 attributed to the group also known as La Mara Salvatrucha, which recruits youths from El Salvador and Honduras.

The violence, including the 2016 slayings of two teenage girls in Brentwood, led to congressional hearings and a visit to Long Island from President Donald Trump, who appeared to reference the Portillo case directly, saying MS-13 members “have transformed peaceful parks in beautiful neighborhoods into bloodstained killing fields.”

For Portillo, prosecutors had argued for a 60-year sentence, citing the brutality and extensive planning of the execution-style killings.

“The defendant’s conduct was not just extremely serious, it was evil,” they wrote.

They also gave a bleak assessment of Portillo's potential reform, saying he had already been involved in two violent jailhouse assaults, faced high school disciplinary issues and had committed the massacre while undergoing counseling to avoid gang involvement, violence and criminal detention.

In a defense submission, lawyers described their client's largely unsupervised childhood and wrote that Portillo told a doctor that he joined the gang to gain respect and more access to friends, women and marijuana.

They urged a judge to reject a Probation Department recommendation of life in prison, saying they could find no case in which a 17-year-old had been sentenced to life for killing at age 15.