As Attorney General Eric Holder prepares to announce his resignation later today, speculation now turns to who could replace him to lead the Justice Department.

Holder has said he will continue as attorney general until his successor is confirmed.

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Here's a look at four people President Obama could select as the next attorney general.

JANET NAPOLITANO

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She served in the Obama administration once before, and she could return again for the attorney general position, a job some say she had previously angled for. Napolitano, 56, was the first woman to serve as Homeland Security Secretary from 2009 to 2013, a post she left to become the president of the University of California system. She previously served as governor of Arizona from 2003 to 2009 and was also an attorney general and U.S. Attorney for the state.

Asked last year if she left her post leading the Department of Homeland Security because she wasn't made Attorney General, Napolitano said, "No, that's inaccurate."

DEVAL PATRICK

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His previous experience in the Justice Department could boost his chances of becoming the next attorney general. The 58-year-old Democratic governor has served two terms representing the commonwealth. In President Bill Clinton's administration, Patrick served in the nation's top civil rights position as Assistant Attorney General for Civil Rights. Patrick is also a close friend of the Obama's and is slated to be in Washington, D.C. later today.

Patrick shot down speculation he's eyeing the attorney general slot, reportedly saying today "That's an enormously important job but it's not one for me right now."

KATHRYN RUEMMLER

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She is currently a partner in the Litigation Department at Latham & Watkins LLP, but she has worked in the Obama administration before. Most recently, she was counsel to the president, where she was one of Obama's top advisors.

Ruemmler , 43, also worked in the Department of Justice as Priniciptal Associate Deputy Attorney General and was an associate counsel to President Bill Clinton.

DONALD VERRILLI

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He currently serves as the country's Solicitor General, a post he's held since 2011 when he was nominated to the position vacated by current Supreme Court Justice Elena Kagan. He also previously served as deputy counsel to President Obama and as an associate deputy attorney general at the DOJ.

Verrilli, 57, was the government's top lawyer who defended the president's healthcare plan before the Supreme Court in 2012.