PHILADELPHIA — A Pennsylvania woman who called herself “Jihad Jane” online pleaded guilty Tuesday to her role in a plot to kill a Swedish cartoonist who had offended Muslims.

Colleen LaRose, 47, helped foreign terror suspects intent on starting a holy war in Europe and South Asia, prosecutors said.

LaRose, who also was accused of using the online screen name “Fatima LaRose,” has been in custody since October 2009 and faces a possible life sentence under the four charges to which she pleaded guilty.

Speaking clearly but quietly, LaRose said Tuesday she had never been treated for any mental health problems and was entering her plea freely. She whispered a few comments to her lawyers, some of them prompting a smile from public defender Mark T. Wilson.

Wilson declined to comment afterward. “We’ll have a lot to say at sentencing,” he said.

LaRose and co-defendant Jamie Paulin-Ramirez of Leadville, Colo., are the rare U.S. women charged with terrorism. Paulin-Ramirez pleaded not guilty after being arrested in Ireland with other terror suspects.

A March 2010 indictment charged LaRose with conspiring with jihadist fighters and pledging to commit murder in the name of a Muslim holy war, or jihad. The indictment was announced hours after authorities arrested seven suspected terrorists in Ireland allegedly linked to LaRose.

In e-mails recovered by the FBI over 15 months, LaRose agreed to marry an online contact from South Asia so he could move to Europe. She also agreed to become a martyr, the indictment said.

The man she had agreed to marry told her in a March 2009 e-mail to go to Sweden to find the artist, Lars Vilks, who had depicted the Prophet Muhammad with the body of a dog, the indictment said.

Vilks has questioned the sophistication of the plotters but said he is glad LaRose never got to him.

LaRose pleaded guilty Tuesday to four counts: conspiracy to support terrorists, conspiracy to kill in a foreign country, lying to investigators and attempted identity theft.

LaRose and her co-conspirators discussed that her appearance and American citizenship would help her blend in while carrying out their plans, prosecutors said.

“Today’s guilty plea, by a woman from suburban America who plotted with others to commit murder overseas and to provide material support to terrorists, underscores the evolving nature of the threat we face,” said Assistant U.S. Attorney General David Kris.

Both LaRose and Paulin-Ramirez led troubled lives, LaRose having survived a suicide attempt and Paulin-Ramirez, according to her mother, an abusive first marriage and a childhood marked by bullying.

LaRose, born in Michigan, moved to Texas as a girl and had married twice by age 24. Her first marriage came at 16, to a man twice her age. Both unions were long over by the time she met Pennsylvanian Kurt Gorman in 2005.

LaRose lived with Gorman and his father in Pennsburg, caring for the older man while Gorman worked at his family’s small business, Gorman said last year. He called her a “good-hearted person” who mostly stayed around the house.

But her online ties grew to a loose band of allegedly violent co-conspirators from around the world, prosecutors said.