Mohamud made it to the country with the funds, court records show, and while there, he was trained by al-Nusrah in weapons and tactics, including how to enter a structure and kill people inside.
Mohamud's brother, Abdifatah Aden, was killed in June 2014, and there is no evidence he and Mohamud ever met face-to-face, court documents filed by prosecutors say. Mohamud returned to the United States that same month and began to recruit others for a terrorist plot — possibly involving killing military personnel in Texas, the documents say.
It is unclear how far along he got in his effort. In September, court documents filed by prosecutors say, Mohamud and three other men went to a central Ohio shooting range, where Mohamud taught two of them how to shoot a handgun. But Mohamud's defense attorney wrote in court papers that by the end of November 2014, Mohamud had "completely abandoned" any plans for terrorism.
The FBI arrested Mohamud in February 2015, and court documents say he lied to law enforcement about his time overseas.
Prosecutors had asked that Mohamud be sentenced to 23 years in federal prison. Defense attorneys had not requested a specific penalty but noted that Mohamud was remorseful for what he had done. In court filings, Mohamud's defense attorneys wrote that Mohamud was heavily influenced by his brother and fully radicalized when he traveled to Syria, though once home, he "realized the immoral and illegal nature of terrorist ideology."
"Mr. Mohamud already appreciates the seriousness of his conduct and feels nothing but remorse for his willingness to embrace a violent and dangerous ideology," Mohamud's defense attorneys wrote. "This self-awareness will ensure that Defendant never again poses a threat of danger to others, or to the United States."
Mohamud, who was born in Somalia and came to the United States just before his second birthday, is a naturalized citizen, though prosecutors wrote in court papers that obtaining that status was meant to further his and his brother's terrorist plan.
Prosecutors wrote that Mohamud, who had been a legal permanent resident since 1993, had begun the naturalization process only after communicating with at least one person linked to a terrorist organization, and he sent his brother a message pledging to join him as a fighter overseas in September 2013. That was months before he took his oath of allegiance to the United States at a naturalization ceremony in February 2014.
Prosecutors wrote that Mohamud had also posted a picture showing armed fighters of the Islamic State in March 2013. He wrote on his naturalization application that he had in no way been associated with a terrorist organization, nor had he advocated the overthrow of any government by force or violence.
The Justice Department under Attorney General Jeff Sessions has sought to highlight links between terrorism and immigration, releasing data last week that said 73 percent of terrorism convictions in the United States have involved individuals who were born in other countries. Analysts, though, questioned the department's methodology, which counted people captured overseas, extradited and brought to the United States to face trial the same as those who emigrated to the United States and were charged with terrorism offenses years later.
A Department of Homeland Security report last year found that citizenship is an "unreliable" indicator of the threat someone poses.