Algerian born Ali Damache has unexpectedly pleaded guilty in a Co Waterford court to a single count of sending a menacing message by telephone to an American Muslim activist.

Reuters reports that while Damache’s guilty plea was unexpected, it will help the US extradite him more quickly for separate terrorism charges. Damache has been living in Ireland for nearly a decade, but has been held in the country for the past three years.

The menacing message charge was unrelated to Damache’s involvement with so-called Jihad Jane, Pennsylvania native Colleen LaRose, and their plotting to kill cartoonist Lars Vilks.

The charges which Damache pleaded guilty to in Waterford were related to the 2009 Christmas Day attempt by a Nigerian man, Umar Farouk Abdulmutallab, to set off explosives hidden in his underwear on a Northwest Airlines flight from Amsterdam to Detroit. Abdulmutallab has pleaded guilty and is serving a life sentence.

On Wednesday in Waterford, Damache pleaded guilty to threatening Detroit based Muslim-American activist Majed Moughni who had organized a rally to condemn the bombing attempt outside a courthouse where Abdulmutallab was appearing.

"I would put a bullet in your head because you are a hypocrite," the then-unidentified caller said to Moughni, who had recorded the phone call.

After Damache pleaded guilty on Wednesday, Moughni said to Reuters, "Hopefully it sends a message, that as a Muslim, I am on the same side as America, and hopefully it will encourage others to speak up as I did to protect our freedoms."

Damache was sentenced to serve four years in prison with the last year suspended on Wednesday in Irish court. He was credited for the three years he had been held for already and was set free immediately.

However, mere moments later he was arrested by the FBI and is expected to sit extradition hearings on Thursday in Dublin. American authorities had been waiting for the menacing messages trial to wrap up so they could begin their extradition trial.

The American charges against Damache are far more serious than the trial that wrapped up on Wednesday. Damache is accused of conspiracy to provide material support to terrorists - specifically, by luring two American-born women Muslim converts to Ireland in 2009.

Colleen LaRose, otherwise known as ‘Jihad Jane,’ has already pleaded guilty in the U.S. to conspiring with Damache to attempt to kill Swedish arts Lars Vilks, who enraged the Muslim community when he published a cartoon depicting the Prophet Mohammed with the head of a dog.

The other American woman Damache lured to Ireland, Jamie Paulin Ramirez, married Damache the day she arrived in Ireland in September 2009. She has also pleaded guilty in U.S. court to flying to Europe to help terrorists.

A third defendant, Khalid Mohammed, a Maryland high school honor student arrested at age 18, also pleaded guilty.