(Colleen LaRose a.k.a. "Jihad Jane")

Colleen LaRose, 50, faced a life sentence but received a reduced term due to her cooperation with investigators. She pleaded guilty in 2009 for following orders from alleged al Qaeda operatives to kill Lars Vilks, an artist who drew the Prophet Mohammed's head on a dog's body.

"This is a sentencing that people are watching," Assistant U.S. Attorney Jennifer Arbitter Williams said on Monday, according to The Huffington Post. "Ms. LaRose had such a big impact in the public and press because she really did change the face of what the world thought of as a violent jihadist. It was scary for people to hear that Ms. LaRose could have been radicalized simply online in the U.S."

LaRose took on the name "Jihad Jane" after becoming involved in an online Muslim community and traveled to Europe to participate in the plot. But she became impatient, returning to Philadelphia six weeks later where she was arrested.

At Monday's hearing, LaRose apologized, saying "I was in a trance and I couldn't see anything else," according to The Huffington Post.

Read Reuters' comprehensive biography of LaRose here.

Reach Senior News Editor Melissah Yang here. Follow her on Twitter @MelissahYang.