Zacharia Abdurahman is seven months into a 10-year term at the federal prison in Sandstone, Minn., sentenced last fall with eight other young Twin Cities men for conspiring to join the terrorist group ISIS.

Although he's 90 miles away, his father, Yusuf, works hard to make sure the two don't grow worlds apart — sending him weekly motivational messages and trading book recommendations. "He's getting wiser," Yusuf Abdurahman said. "More thoughtful."

But it's a process the 21-year-old Zacharia is undergoing without much help from the federal prison system. Abdurahman is one of roughly 460 federal inmates considered extremists by prison officials. But like the rest, he gets no targeted services to unpack what attracted him to terrorism and guide him away from extremist views, according to Minnesota judges and parole authorities who have watched the federal cases.

For months, officials in Minnesota have complained that federal prisons could become a breeding ground for terror in the absence of tailored programming for these young convicts, and now federal investigators are analyzing the U.S. Bureau of Prisons' approach to deradicalization.

"When they come out, we've got to supervise them," Chief U.S. District Judge John Tunheim said in an interview. "You don't want to have them come back from prison worse than when you sent them."

Some of the loudest protests have come from federal law enforcement officials in Minnesota because they'll be responsible as the young men and women start coming home after prison sentences in terror cases. The state has seen more than 30 defendants charged in Al-Shabab and ISIS-related cases in the past decade. About 10 are now out of prison on supervision, with several more expected in the next year.

Zacharia Yusuf Abdurahman is seven months into a 10-year term at the federal prison in Sandstone, Minn.

"The biggest concern for us is the piece the [Bureau of Prisons] plays, because that is the longest period of time for all this," Chief U.S. Probation Officer Kevin Lowry said. "If there's no programming and then they come out ... it will be just short of impossible maybe to turn them around."

Lowry's office is leading a program introduced last year, initially to evaluate some of the nine young men convicted in the ISIS investigation. The district contracted with Daniel Koehler, a German expert on radicalization, who has worked with both neo-Nazis and jihadists, and has since trained 11 of Minnesota's 50 federal probation officers. Koehler has also helped the office instruct law enforcement from nine other districts — and the Bureau of Prisons — since last spring.

But Minnesota's program handles cases only from the time of arrest to sentencing, and again only after the offender has been released from prison. That leaves the intervening years "a black box" that could raise the risk of deeper radicalization, Koehler has said.

"When there is nothing, no counseling in place, no psychologists or prison imams or anyone who can challenge the beliefs or even assess the radicalization stage ... there's nothing that actually prevents them from spreading their thoughts," Koehler testified at a Minneapolis hearing last year.

Justin Long, a federal prisons spokesman, said the agency monitors "all telephonic communication of inmates" linked to terrorism and shares intelligence with agencies like the FBI. But the bureau hasn't departed from its traditional approach — programs like vocational training or substance abuse treatment, he said.

"In this case, that's a shortcoming," said Matthew Levitt, a fellow with the Washington Institute for Near East Policy. In March, the think tank urged the Trump administration to adopt "full-fledged rehabilitation and reintegration programs" for radicalized inmates. "Programs in prisons would focus on contesting violent extremist narratives and promoting the idea that there are ways — certainly in the U.S. — of challenging policies with which one disagrees short of supporting or engaging in violence."

In May, the Office of the Inspector General opened an audit of the Bureau of Prisons' "counterterrorism efforts" for inmates who are due to be released from prison within the next few years.

The probe began after U.S. security officials issued a bulletin that predicted that some of the more than 90 people serving terror sentences who are expected released within five years "will probably re-engage in terrorist activity."

Lowry says federal prison officials initially balked at creating programs for extremists because they represent a small portion of the U.S. federal prison population. About 360 inmates have ties to international terrorism and 100 are domestic extremists, he said.

But, Lowry added, "the most unacceptable answer I think is doing nothing — which comes with the greatest liability in life."

Minnesota officials do, however, say the bureau is now paying more attention.

Prison staff attended a May training event brokered by Minnesota and led by the United Kingdom's National Offender Management Service (NOMS), which has been developing intervention programming for about a decade.

NOMS works one-on-one with inmates in what it calls "Healthy Identity Interventions" and last month in Minneapolis explained the tailored counseling it gives extremists, such as deconstructing the ideology behind their crimes. Other sessions examine how inmates can begin to make new commitments in life or re-establish old relationships once abandoned.

Long, the bureau's spokesman, said prison officials appreciated the training and that his agency "is committed to exploring evidence-based practices in understanding the factors that lead an individual to involvement in violent extremist activity."

Last month, Yusuf Abdurahman drove up to the Sandstone prison to visit his son for Father's Day.

Zacharia told him that he and his fellow Muslim inmates are now the only religious group without a chaplain, after an imam was forced out by a small coterie of more extreme inmates. Yusuf is now working to get a Minneapolis imam approved to begin visiting the prison.

Zacharia, meanwhile, keeps himself busy by reading and helping other inmates explore basic Islamic textbooks, Yusuf Abdurahman said. Beyond being a connection to the outside world for his son, Yusuf Abdurahman also occasionally lends help interpreting certain religious texts or rulings.

"If nothing happens in the prisons," Abdurahman said, "some inmates may think, 'Maybe I did come here because an informant recruited us.' You then believe you're in prison not because of what you did but because of your faith."

Stephen Montemayor • 612-673-1755

Twitter: @smontemayor