Nine Twin Cities men who were part of the nation's largest ISIS conspiracy case will learn their fates this week as a federal judge begins three days of sentencing on Monday.

The hearings cap more than two years of a federal investigation that traced the movement of young Minnesotans to the Middle East to take up arms with the so-called Islamic State. The men who'll be sentenced never made it that far, but they still face hard prison time.

Prosecutors are proposing 15 years for most of the men who pleaded guilty to supporting a terrorist group. But if they cooperated with the government, prosecutors are suggesting sentences of as little as 3.5 years.

For three men who took their cases to trial this year, the penalties could be much stiffer — prosecutors want 30 years in prison for two of them, Abdirahman Daud and Mohamed Farah, and 40 for an alleged leader of the group, Guled Omar.

Guled Ali Omar, Mohamed Abdihamid Farah, Abdirahman Yasin Daud Associated Press

The trio that went to trial was convicted in June after a jury heard audio recordings of the men's own words, secretly captured by a friend working with the FBI. They openly discussed their plans to leave the country using fake passports and boasted about the contacts they had made in Syria.

In one of the tapes, defendant Mohamed Farah told the informant he'd kill an FBI agent who was closing in on him.

"Our backs to the wall, I'm going to kill the one who threatens me," Farah said on the tape, speaking in a mix of Somali and English.

At trial, Farah and the men argued such comments were nothing more than just youthful boasting — they weren't actual threats.

The trial was crushing for family and friends, like Naema Ahmed. She's engaged to one of the men convicted, Abdirahman Daud. She said her own understanding of the case has evolved.

"The boys and the families in the beginning, we were in stage of denial," Ahmed said. "You kind of don't want to believe it. Now we take acceptance to what happened. The biggest thing is, we just want our families back and our boys back."

Ahmed was one of more than a dozen who wrote letters to U.S. District Judge Michael Davis seeking compassion and rehabilitation for the defendants. The men, once seen as leaders and role models in the community, she said, can even help the government in its fight against terrorism recruitment.

Others who wrote similar letters include former employers, mosque officials and prominent Somali-American leaders, including Ilhan Omar, fresh off her historic election to the state Legislature, and Minneapolis City Council Member Abdi Warsame.

So did Mohamud Noor, who runs the Confederation of Somali Community in Minnesota. He thinks the prospect of sending these young men to prison for decades is too long, given their ages. Most of them were in their late teens when they landed on the FBI's radar.

"Expecting to be in jail for many, many years is not something good for young people who are seeking help, who are seeking justice, who are seeking guidance," Noor said.

The defendants hope Davis will consider lighter prison sentences, combined with a system that focuses on re-entry and reconciliation.

Karen Greenberg, director of the Center on National Security at Fordham University, who has been closely following ISIS-related cases around the country, said Davis has distinguished himself nationally for being open to alternative remedies in certain cases.

The mother of Guled Omar, Fadumo Hussein (center), with supporters at the ISIS trial in May 12 in Minneapolis. Doualy Xaykaothao | MPR News file

She notes that he brought in a German counterradicalization expert to assess the defendants' potential for rehabilitation.

"I think there's a chance with this case that it will set some kind of recommendation and pattern for the future," she said. "But there's really no telling, because the judge has really not showed his hand. He's been very even in considering all the elements of the arguments in the case. So I think we don't know."

Looking to other examples around the country, she says the judge very well could side with the government and deliver lengthy prison sentences.

Federal authorities argue that stiff penalties might deter other young Americans from making the same mistakes.

Judges presiding over ISIS cases used to dole out lighter punishment for younger offenders, Greenberg said.

And there's a growing sense among national security experts that the United States cannot solve the problem of terror recruitment through incarceration alone. The chances of young radicalized people receiving proper interventions in prison are slim, Greenberg said.

"If we put them in jail for young ages — and put them in jail for 15 years — we know we're derailing their lives and creating more of a problem," Greenberg said.

However, lighter sentences haven't been the trend lately, and Minneapolis is seen as home to one of the most high-profile ISIS cases in the nation.