ST. PAUL, Minn - Federal authorities say a massive investigation into the disappearances of about 20 young Somali men from Minnesota has taken a significant step forward with a seventh arrest in the case.

This week, a grand jury indicted Omer Abdi Mohamed on charges of supporting terrorists. The 24-year-old St. Anthony man had his first court appearance Thursday.

Investigators have been trying to determine who recruited young Somali-American men from Minnesota to fight in one of the deadliest places on earth. For more than a year, that question has gone unanswered.

The indictment against Omer Mohamed alleges he was directly involved in sending six young men to the chaos of their East African homeland. The indictment said he, "knowingly committed and caused the commission" of the disappearances of the first wave of fighters who traveled to Somalia, back in December 2007.

One of them included Shirwa Ahmed of Minneapolis. Authorities believe Ahmed became the first American suicide bomber when he allegedly blew up himself and several others more than a year ago in Somalia.

But Omer Mohamed's attorney, Peter Wold, said his client wasn't involved in any kind of conspiracy.

"He didn't have a role," he said. "I mean, he knew people that went to Somalia, as did everybody else in that community. It's a tight-knit community. His country of birth was invaded by Ethiopia. That brought passion to a lot of people, as it would you or me."

Wold was referring to the climate in late 2007 in Somali communities around the globe, including the Twin Cities, during the Ethiopian occupation of Somalia.

Friends of the missing American fighters have said that the young men wanted to defend their homeland. But the hard-line Islamic group they allegedly joined, al-Shabaab, has continued down a violent path even after the Ethiopian soldiers pulled out of the country this year. The U-S considers al-Shabaab a terrorist group.

To read full Minnesota Public Radio story — Go Here Now.