Robert Christian Boes Hansen (February 15, 1939 – August 21, 2014), also known as the Butcher Baker, was an American serial killer active in Anchorage, Alaska, between 1972 and 1983, abducting, raping and murdering at least seventeen women. Many of his victims were released by Hansen into the wilderness and hunted with a Ruger Mini-14 and hunting knives. Hansen was captured in 1983 and sentenced to 461 years' imprisonment without the possibility of parole. He died in 2014 of natural causes at age 75.

While serving a prison sentence for arson in the early 1960s, Hansen was diagnosed with manic depression with periodic schizophrenic episodes. The psychiatrist who made the diagnosis noted that Hansen had an "infantile personality" and that he was obsessed with getting back at people whom he felt had wronged him.

Robert Hansen was born in Estherville, Iowa, on February 15, 1939, the elder of two children to an American mother, Edna Margret Hansen (née Petersen; October 27, 1916 – April 24, 2005) and a Danish father, local baker Christian "Chris" Hansen (September 16, 1907 – August 12, 1983). Robert was employed at his father's bakery. The family moved to Richmond, California, in 1942, but returned to Iowa in 1949 and settled in the city of Pocahontas.

In his youth, Hansen was painfully shy, had a stutter and suffered severe acne that left him permanently scarred. Throughout childhood and adolescence, he was described as a quiet loner who had a difficult relationship with his domineering father. Hansen took to practicing both hunting and archery, often finding refuge in those pastimes. In 1957, Hansen enlisted in the United States Army Reserve and served for one year before being discharged. He later worked as an assistant drill instructor at a police academy in Pocahontas. There, he began a relationship with a younger woman, whom he married in 1960.

On December 7, 1960, Hansen was arrested for burning down a Pocahontas County Iowa school bus garage, as revenge for his mistreatment in high school. He served twenty months of a three-year prison sentence in Anamosa State Penitentiary, during which his first wife divorced him. During his incarceration, Hansen was diagnosed with manic depression with periodic schizophrenic episodes. The psychiatrist who made the diagnosis noted that Hansen had an "infantile personality" and was obsessed with getting back at people he felt had wronged him.

Over the next few years, Hansen was jailed several times for petty theft. In 1967 he moved to Anchorage, Alaska, with his second wife, whom he had married in 1963 and with whom he had two children. In Anchorage, Hansen opened his own bakery, was well-liked by his neighbors and set several local hunting records.

In December 1971, Hansen was arrested twice, first for abducting and attempting to rape an unidentified housewife, then for raping an unidentified sex worker. He pleaded no contest to assault with a deadly weapon in the former offense; the rape charge involving the sex worker was dropped as part of a plea bargain. Hansen was sentenced to five years in prison. After serving six months of his sentence, he was placed on a work release program and released to a halfway house.

In 1976, Hansen pleaded guilty to larceny after he attempted to steal a chainsaw from an Anchorage Fred Meyer store. He was sentenced to five years in prison and required to receive psychiatric treatment for his manic depression. The Alaska Supreme Court reduced Hansen's sentence, and he was released with time served.