Mr. John Nielsen was appointed as UN Police Commissioner in the United Nations Mission in Liberia on 13 April 2012. Prior to this, he served with UNMIL as Deputy Police Commissioner and also as Senior Police Adviser responsible for capacity development of the Liberian National Police and advisor to the Inspector General of Police. He worked on many projects in support of the security sector reform in Liberia such as the creation of the Liberia National Police and the Bureau of Immigration and Naturalization strategic development plans, the formation of the Emergency Response Unit, review and development of policies and procedures and the establishment of the Professional Standards Division of the Liberia National Police.

In 2004, he excelled as Senior Police Advisor in Haiti where he supported the peacekeeping mission and capacity building of law enforcement institutions. In the US police, Mr. Nielsen started his law enforcement career as police officer, assumed several leadership responsibilities until he was commended and appointed as Commissioner of Public Safety for the City of Albany, New York.

He is a career security expert with over 40 years professional knowledge in diverse fields of public safety administration with specialism in domestic and international law enforcement. In his career, he has contributed immensely to ensuring appropriate balance of public safety, law enforcement, and protection of civil liberties, human rights and promoting gender equity.

In accomplishing his policing career he attended the Federal Bureau of Investigation National academy, Quantico, VA and went further to complete a Bachelor degree in Social sciences in the United States. He is the recipient of numerous professional and civic citations for professional accomplishment.