A movie was made about it. It's pretty good, too.
Detailed story about him which may explain why he became what he became:
https://en.wikipedia.org/wiki/Anders_Behring_Breivik
During her pregnancy, Anders Breivik’s mother developed a disdain for her son. She claimed that he was a "nasty child" and that he was "kicking her on purpose". She had wanted to abort him but by the time she returned to Norway from the UK, she had passed the three-month threshold for an abortion. Psychologists reports later stated that she thought that Breivik was a "fundamentally nasty and evil child and determined to destroy her." She stopped breastfeeding her son early on because he was "sucking the life out of her."
[47] He spent the first year of his life in London until his parents divorced when he was a year old.
When Breivik was four, living in Oslo's Frogner district (now in
Frogner borough), two reports were filed expressing concern about his mental health.
[48] A
psychologist in one of the reports made a note of the boy's peculiar smile, suggesting it was not anchored in his emotions but was rather a deliberate response to his environment.
[49] In another report by psychologists from Norway's centre for child and youth psychiatry (SSBU), concerns were raised about how he was treated by his mother: "She 'sexualised' the young Breivik, hit him, and frequently told him that she wished that he were dead." In the report, Wenche Behring is described as "a woman with an extremely difficult upbringing,
borderline personality disorder and an all-encompassing if only partially visible depression" who "projects her primitive aggressive and sexual fantasies onto him [Breivik]".
[50] Psychiatrists recommended he be removed from his mother and placed into foster care when he was 4 years old, as she was heavily emotionally and psychologically abusive towards him.
[47] Breivik's mother fled her abusive home at age 17 and soon after that became a teenage mother. In her thirties, she was married to Jens Breivik when Anders was born.
[47]
In 1983 and 1984, at the clinic, National Centre for Child and Adolescent Psychiatry (
SSBU), one
[51] psychologist and one psychiatrist wanted Breivik forcibly removed from his mother; the clinic had placed a care order for the boy but this was not carried out by the
Child Welfare Service.
Breivik's mother moved back to Oslo, where she borrowed
[52] Jens Breivik's apartment in the Frogner district (now in
Frogner borough). The neighbors claimed that there were noises of fights and that the mother left her children completely alone for extended periods of time, while she was working as a nurse. In 1981, Breivik's mother applied for
welfare benefits, specifically [monetary payment, or] financial aid;
[52] in 1982, she applied for
respite care for her son. She says that she was overwhelmed with the boy and unable to care for him. She described him to be "clingy and demanding." Breivik was then placed [in cooperation with the Child Welfare Service,] with a young couple. This couple later told police that the mother, when bringing two-year-old Breivik to the house, had asked that he be allowed to touch the man's ***** because he had no one to compare himself to in terms of appearance; "He only saw [or was used to seeing girls'
pee holes—]
jentetisser", the mother told the couple, according to the couple's undated statement to police.
[53]
In February 1983, on the advice of her neighbors, Breivik's mother sought help from the National Centre for Child and Adolescent Psychiatry; the mother and Breivik were
outpatients, and they stayed there at daytime - for about one month. The conclusion of the stay from the psychiatrists was that Breivik should be placed in the foster care system and had to be removed from his mother for him to develop normally. The justification for this was several observations. Breivik had little emotional engagement. He did not show joy. He didn't cry when he was hurt. He made no attempts to play with other children. He was also extremely clean and became anxious when his toys weren't in order. Psychologists believed that he had become this way because of the negative reactions his mother displayed to any emotion he showed. They thought that she had punished him and reacted extremely negatively to him displaying emotions that had led him to become devoid of any visible emotions. His mother had also claimed that he was unclean and that she constantly had to care for him and run after him. Psychologists believed that Breivik had become this clean because of fear of punishment from his mother. He didn't show the normal level of uncleanliness of a four-year-old. Breivik seemed extremely careful and controlled. He had no repertoire on how to express emotions normally. During long phases of emotional voidness, he would rarely erupt and display extreme uncontrolled emotions.
[47]
Reports of the staff said that his mother had told Breivik while she knew that she was being observed by health personnel that she "wished that he was dead". At the same time she bound him emotionally to her, alternating between great affection and extreme cruelty from one moment to the next. This was an unacceptable situation for a four-year-old to be in, according to the psychiatrists. The report from 1983 stated "Anders is a victim of his mother's projections of paranoid-aggressive and sexual fears toward men in general", and "she projects onto him her own primitive, aggressive and sexual fantasies; all the qualities in men that she regards as dangerous and aggressive." Breivik reacted very negatively to his mother. He alternated between clinginess, petty aggression and extreme childishness.
[47] The final conclusion of the observation was that "The family is in dire need of help. Anders should be removed from the family and given a better standard of care; the mother is provoked by him and remains in an ambivalent position which prevents him from developing on his own terms. Anders has become an anxious, passive child that averts making contact. He displays a manic defense mechanism of restless activity and a feigned, deflecting smile. Considering the profoundly pathological relationship between Anders and his mother it is crucial to make an early effort to ward off a severely skewed development in the boy." However, Child Welfare Services did not follow this recommendation. Instead, he was placed in respite care only during the weekends. SSBU hoped that eventually he would be placed into foster care.
[47]
However when Breivik's father, Jens Breivik, learned of the situation he filed for custody. Although Breivik's mother had agreed to have him put in respite care, after Jens had filed for custody she demanded that Breivik be put back into full custody with her. Both the mother and father involved lawyers. Eventually, the case was dropped because the Welfare Services thought that they wouldn't be able to provide enough evidence in court to warrant the placement of Breivik in foster care. One of the main reasons for this was the testimony of staff from the Vigelandsparken nursery, which Breivik had been attending since 1981. They described him as a happy child and claimed that nothing was wrong or had been wrong with him all along. During all of this the SSBU maintained their stances and said "urgent action is crucially needed to prevent a severely skewed development in the boy". The SSBU wrote Child Welfare Services a letter claiming that an order should be placed to have Breivik removed by force. In 1984, a hearing in front of Barnevernsnemnda (the municipal child welfare committee) took place on whether Breivik's mother should lose custody of him. Child Welfare Service lost the case; the agency was represented by a social worker with no experience of representing a case in front of the committee.
[52] It was ruled that the family should be supervised. However, after only three visits the supervision was discontinued. Breivik was never again put into respite care or foster care.
[47]