Carruthers was born and raised in Pahiatua, New Zealand. He went on to study law, graduating LLB from Victoria University of Wellington in 1962. He completed his LLM with honours two years later. Carruthers is married and has five children.
Career
Legal practice
Carruthers practised law in Wellington and Pahiatua for 20 years before moving to Palmerston North.
Judiciary
In 1985, Carruthers was appointed as a judge in the Family Court in Wellington. Five years later he became a judge in the Youth Court, eventually being appointed as Principal Youth Court Judge. In 2000, Carruthers was asked to lead a Ministerial Taskforce on Youth Offending to come up with initiatives designed to reduce youth crime after Ministry of Justice figures showed that "over the 1990s, offending by 10- to 16-year-olds increased by 55%". In 2001, Carruthers was appointed as Chief District Court Judge, a position he held until 2005. Carruthers also served as a judge on the High Court of Vanuatu.
New Zealand Parole Board
Carruthers was appointed Chairman of the New Zealand Parole Board in 2005, a position he held until 2012. He was head of the Board when it made the decision to release Graeme Burton from prison in July 2006. Six months later, Burton shot and killed Karl Kuchenbecker in the hills of Wainuiomata and injured a number of others. Shortly after the murder, Carruthers fronted up for media interviews and spoke about how devastated he felt. He admitted to an "extraordinary sense of personal responsibility" that Burton's release had resulted in two boys losing their father.
Independent Police Conduct Authority
In April 2012, Parliament appointed Carruthers as the new chairman of the Independent Police Conduct Authority.
Public speeches
Carruthers has given speeches at numerous conferences and seminars both in New Zealand and overseas. For many years he has pushed for a more humane approach to dealing with criminal offenders advocating, in particular, for increased use of restorative and therapeutic justice approaches. He has held a number of public and charitable offices and recommended greater focus on education, and interventions for youth and families rather than locking up more and more offenders. Speaking at a criminology conference in November 2012, Carruthers commented on the reduction in New Zealand'scrime rate. He believes the drop may be due to efforts to reduce the number of teenagers being suspended or expelled from school.