Ornaith resided in Oakland, California in 2001. She and her husband, Kieran Murphy, were in the process of divorcing late in the year. They had moved together from the United States to Ireland in the late 1960s. Ornaith was active in the sailing community and was an occasional contributor to sailing magazines. She owned a 1980 39-foot fiberglass auxillary sailboat named Sola III. The vessel has dark blue circular emblems with one gray swirl painted on both of her sides. Ornaith normally berthed the boat at the Oakland Marina in the Jack London Square area of the city.

Ornaith was last seen in Oakland on December 16, the day after her estranged husband's disappearance. The vessel disappeared on the same day as Ornaith; it has never been located. The boat was captured on a video surveillance camera pulling out of the Oakland Marina at 8:36 p.m. on December 15. It had about one week's worth of food on it when it disappeared, but no safety or foul weather gear.

Kieran and Ornaith planned to meet on the day of his disappearance to discuss legal issues. Ornaith was seen working on her boat that day. A man fitting Kieran's description was seen near the boat on the evening of his disappearance, but it was never established that the man was in fact Kieran. Witnesses reported hearing loud banging sounds coming from near the Sola III the evening he disappeared. The witnesses could not be sure that the sounds were gunshots, however. The next day, December 16, Ornaith called her niece from the Sola III. She said she was in a marina in Berkeley. Ornaith's niece invited her to breakfast, but Ornaith declined the invitation. She has never been seen or heard from again.

Ornaith and Kieran are described as a witty, intelligent couple who enjoy reading classic literature. They amassed a small fortune through real estate speculation and have two sons together. Their marriage crumbled after Kieran had an extra-marital affair. Kieran was living in an apartment in the Nob Hill area of San Francisco when he disappeared; Ornaith resided with her niece near Jack London Square in Oakland, near her boat. Both were the defendants of a lawsuit at the time of their disappearance; one of the buildings they owned had caught fire and a child had been badly burned.

Ornaith's family reported her as a missing person from Oakland. The estranged couple may be traveling together aboard the vessel. Another theory is that Ornaith shot Kieran and committed suicide shortly afterwards. There has been no evidence to support this, however, beyond the noises heard by witnesses.

Kieran was supposed to vacation in Mexico shortly after he disappeared. His and Ornaith's sons say it would be uncharacteristic of them to leave without warning. The Sola III was not equipped for an extended cruise and Kieran did not know how to sail it. The United States Coast Guard has been involved in the search for Kieran and Ornaith, but no evidence has been discovered. Neither of the couple's credit cards or bank accounts have been used since their disappearances. Their cases remain unsolved, but their disappearances are considered suspicious.