COSTA MESA – Police have arrested the former fiancée of a Costa Mesa man accused of fatally shooting two Orange Coast College students and dismembering one of them, with investigators alleging that she acted as an “accessory after the fact.”

Costa Mesa detectives Tuesday afternoon arrested Rachel Buffett, 25, of Long Beach as an accessory in the 2010 murders of Samuel Herr, 26, and Juri “Julie” Kibuishi, 23, a police statement said.

Police did not outline what role they believe Buffett had in the killings.

Daniel Wozniak, who was engaged to Buffett before he was arrested in connection with the killings, faces two felony counts of special-circumstances murder. If convicted, he could face the death penalty.

Wozniak, a community theater actor, confessed to Costa Mesa police detectives that he had killed Herr and Kibuishi as part of a scheme to access Herr’s bank account, transcripts of an Orange County grand jury session earlier this year show.

Authorities allege that on May 21, 2010, Wozniak lured Herr, his neighbor, to a theater on the Los Alamitos Joint Forces Training Base, where prosecutors believe he shot Herr twice in the head before stealing his ATM card, wallet and cellphone.

Later that evening, prosecutors allege, Wozniak used Herr’s cellphone to send a text message to Kibuishi, a friend of Herr’s, to lure her to his apartment. Authorities believe Wozniak shot Kibuishi twice in the head, and then removed some of her clothing to make it look like she had been sexually assaulted.

Wozniak returned to the Los Alamitos theater, authorities allege, where he is accused of cutting off Herr’s head, left arm and right hand before dispersing the body parts in the theater and at El Dorado Park in Long Beach.

Steve Herr, Samuel Herr’s father, called police after discovering Kibuishi’s body at his son’s apartment. During the police investigation, a 17-year-old was caught using Herr’s debit card to withdraw cash at various ATMs in Long Beach. The juvenile told investigators that he was withdrawing money for Wozniak, police said.

Wozniak was arrested during his bachelor party at a Huntington Beach restaurant May 26, 2010. Authorities say Wozniak and Buffett were scheduled to be married several days later.

Wozniak pleaded not guilty to the murder charges in early May and is awaiting trial.

Police say Buffett was the focus of an “ongoing investigation” since the killings and had been “previously contacted and interviewed by detectives.” A statement released by Costa Mesa police Tuesday said detectives compared information from those interviews, as well as interviews with other witnesses, and determined there was “probable cause to arrest Buffett as an accessory after the fact in this murder case.”

The case against Buffett is being turned over to the District Attorney’s Office, police said, where prosecutors will decide whether criminal charges will be filed.

Register staff writers Vik Jolly and Larry Welborn contributed to this report.

Contact the writer: 714-796-7939 or semery@ocregister.com