[3] Born and raised in San Francisco, California[4] by his devoutly Pentecostal grandmother, Nelson exhibited bizarre behavior as a child, which was compounded by head injuries he sustained in a bicycling accident at age 10.

Nelson began committing numerous rapes and murders in February 1926, primarily in the West Coast cities of San Francisco and Portland, Oregon.

Posing as a mild-mannered and charming Christian drifter, Nelson used the pretext of renting a room in the landladies' boarding houses to make contact with them before attacking.

[13] Described as a "psychotic prodigy,"[14] Nelson exhibited increasingly bizarre, manic behaviors in his childhood, such as talking to invisible people, compulsively quoting Biblical passages, and watching female family members undress.

[15] In his early teenage years, Nelson began frequenting brothels and bars in San Francisco's Barbary Coast red-light district,[3] and contracted a venereal disease.

[16] Nelson began his criminal activities at a young age, and was sentenced to two years in San Quentin State Prison in 1915 after breaking into a cabin in rural Plumas County,[17] which he believed had been abandoned.

"[9] William Pritchard, a psychiatrist who conducted a preliminary interview with him, noted that Nelson spoke of hallucinations and other paranoid delusions: "He has seen faces, heard music, and at times believed people were poisoning him.

[23] Their marriage, however, was short-lived, as Nelson "made her life a living hell"[3] with his jealous rages, bizarre sexual demands, religious delusions, and increasingly violent behavior,[20] leading her to separate from him after cohabiting for only six months.

[23] Martin would later recall various bizarre behaviors she witnessed while living with Nelson, which included protracted disappearances from their home and unusual bathing practices that entailed him pouring glasses of water over his toes.

[35] An autopsy confirmed that Russell had been sexually assaulted after death, and the similarities in the modus operandi between her murder and the San Francisco area slayings led police to assume they were connected.

"[14] In the fall of 1926, Nelson relocated to Portland, Oregon, where he raped and murdered 35-year-old landlady Beata Withers on October 19,[30] her body found by her teenage son, stuffed beneath clothing inside a steamer trunk in the attic of her home.

[30][41][42] The following day, 59-year-old Virginia Grant was murdered in a vacant property she owned on East 22nd Street, her body hidden behind the home's basement furnace.

[44][45] Despite the subsequent similar murders of Grant and Fluke, a coroner's jury of four men and three women was appointed on October 28 to evaluate the "mysterious" death of Withers.

"[48] The following day, November 19, in nearby Burlingame, California, a 28-year-old pregnant woman was attacked while showing her home to a man posing as a potential buyer.

"[53] One local woman called police, claiming that a suspicious man had stayed in her boardinghouse for several days after the Thanksgiving holiday, using the name "Adrian Harris.

"[54] On November 29, the day of Myers' murder, she stated the man told her and other residents that he was leaving to take a train to Vancouver, Washington, and had indicated that he would not be returning.

[54] Before departing, he gave her and another female boarder pieces of jewelry as a gift, which were later confirmed by police to have been owned by Florence Monks, a wealthy widow who had been murdered and raped in her Seattle home on November 23.

[55] In hopes of preventing further murders, law enforcement in California and Oregon issued public safety announcements to citizens; in the San Francisco Bay area, elderly women were advised to take precautions while renting rooms and inviting strangers into their homes.

[58] Two days after Christmas, 23-year-old Bonnie Pace of Kansas City, Missouri, was strangled to death and raped in her home, her body discovered in an upstairs room by her husband.

[66] Randolph's brother, Gideon Gillett, had met "Mr. Harrison" when he first arrived at the residence, and described him as "about thirty-three years old, with a stocky build, dark complexion, and black hair slicked straight back.

[32][76] Nicholas Tabor, a barber who owned a shop next door to the secondhand store, told police he had given a man resembling Nelson a shave, haircut, and massage on the afternoon of June 10.

[69] After the discovery of Cowan's body, Winnipeg City Council posted a C$1,500 reward for information leading to the "conviction of the criminal degenerate" responsible.

[32] A man matching Nelson's description who gave his name as "Mike Mowski" was arrested on June 14 in the Manitoba/Minnesota border town of Warroad by Customs Officers, but he escaped the next day.

"[87] Despite attempts on part of both U.S. and Canadian law enforcement agencies to elicit confessions, Nelson refused to admit to any of the murders of which he was suspected or accused.

"[92] Additionally, over sixty individuals from both Canada and the U.S. testified, many placing Nelson at the scenes of the various crimes or linking him to property stolen from victims' homes.

[96] In late December 1927, Stitt submitted a thirty-page document to Minister of Justice Ernest Lapointe, petitioning for clemency on the grounds that Nelson was insane and that his personal history had been unfairly presented to the jury via the press.

[88] During Nelson's incarceration leading up to his trial, he was examined by Dr. Alvin T. Mathers, chief of the psychiatric ward and Winnipeg General Hospital, on five separate occasions between July 27 and October 24, 1927.

"[92] Nelson was the first serial murderer in American history whose crimes were subject to widespread media attention in newspapers, national magazines, and the then-new medium of the radio.

[86][102] Nelson's confirmed murder count, which exceeded twenty, remained a record high for nearly fifty years until the discovery of Juan Corona's crimes in 1971.

[3] Though Nelson refused to admit to any of the crimes of which he was accused, he has been linked to a total of 22 murders that occurred between 1926 and 1927;[99] his victims consisted nearly exclusively of women, along with one male infant child.