Robert Keeler (defendant) and his wife Teresa Keeler divorced on September 27, 1968. At the time, Mrs. Keeler was pregnant with another man’s child. On February 23, 1969, Mrs. Keeler was driving on a narrow road when another car forced her to pull over. Mr. Keeler came out of the other car and confronted her about her pregnancy. Upon seeing her stomach, Mr. Keeler became angry and struck her in the stomach with his knee, intending to hit the fetus out of her. After he left, Mrs. Keeler called for assistance and underwent a Caesarian section. The fetus was stillborn, with a skull fracture cited as the cause of death. An investigation showed that the skull fracture could have been due to Mr. Keeler’s attack to Mrs. Keeler’s stomach. Evidence at the time showed the fetus was viable on the day of attack. Mrs. Keeler and her doctor had previously detected fetal movement, and at the time the fetus was stillborn, it weighed five pounds and was 18 inches long. An expert estimated that had the fetus been born prematurely on the date of its death, it would have had a 75 percent to 96 percent chance of surviving. Mr. Keeler was charged with the murder of the fetus. In California, Penal Code § 187 criminalizes the murder of a “human being.” Mr. Keeler moved to set aside the information. The lower court denied his motion, and he petitioned for a writ of prohibition from the Supreme Court of California.