Umar Farouk Abdulmutallab, the so-called "underwear bomber," has been sentenced to life in prison after pleading guilty to the attempted bombing of Northwest Airlines Flight 253 on Christmas Day 2009.

The sentence was handed down by U.S. District Court Judge Nancy G. Edmunds in Detroit.

Abdulmutallab, 25, of Kaduna, Nigeria, pleaded guilty on Oct. 12, 2011, to conspiracy to commit an act of terrorism transcending national boundaries; attempted murder within the special aircraft jurisdiction of the United States; willfully placing a destructive device on an aircraft, which was likely to have endangered the safety of the aircraft; attempted use of a weapon of mass destruction; willfully attempting to destroy and wreck a civil aircraft; and three counts of possession of a destructive device in furtherance of a crime of violence.

"As this investigation and prosecution have shown, Umar Farouk Abdulmutallab is a remorseless terrorist who believes it is his duty to kill Americans," said Attorney General Eric Holder in a statement. "For attempting to take the lives of 289 innocent people, he has been appropriately sentenced to serve every day of the rest of his life in prison."

In August 2009, Abdulmutallab traveled to Yemen to become involved in violent "jihad" on behalf of al Qaeda. There, he conspired with other al Qaeda members to bomb a U.S. aircraft over U.S. soil and received an explosive device for that purpose. Abdulmutallab traveled with the bomb concealed in his underwear from Yemen to Africa and then to Amsterdam, the Netherlands, where he boarded Flight 253 on Christmas Day 2009. The bomb contained PETN and TATP, two high explosives, and was designed to be detonated with a syringe containing other chemicals.

Abdulmutallab's purpose in taking the bomb on board Flight 253 was to detonate it during flight, causing the plane to crash and killing the 290 passengers and crew members on board. As Flight 253 was on descent into Detroit Metropolitan Airport, the defendant detonated the bomb, which resulted in a fire, but otherwise did not fully explode. Passengers and flight attendants tackled the defendant and extinguished the fire.