After reading law at the University of Amsterdam, Spong began working as a lawyer in 1973 in Surinam. In 1976 he returned to the Netherlands and started, after taking part in a criminal law specialisation programme, one of the first Dutch law firms specialising exclusively in assistance to criminal defendants (Wladimiroff & Spong).
Gerard Spong handles all criminal cases before courts and courts of appeals and is specialised in appeals in cassation before the Dutch Supreme Court. Spong is a member of the European Criminal Bar Association and also provides legal assistance in extradition cases, disciplinary cases, medical or otherwise, and in criminal cases in the Carribean part of the Kingdom of the Netherlands.
Spong published many articles on criminal law and procedure and regularly gives lectures. In the Handboek Verdediging he wrote the chapter on legal assistance in the cassation procedure and, with Mirto Murray and Roan Lamp, the chapter on legal assistance in the Dutch Carribean. Spong gives postgraduate courses for other lawyers in the Spong Law Academy.
Furthermore Spong published legal thrillers De Breuk (2013) en De uitvaartverzorger (2016) and gave a performance about criminal law in more than 70 theaters in the Netherlands during the 2018-2019 theater season. Spong was appointed Officer in the Order of Orange-Nassau in 2019.
Sidney Smeets read law at Leiden University and history at Utrecht University and was admitted to the bar in 2001 after working in the House of Representatives. He specializes in criminal law and has represented clients in many well publicised cases, both in the Netherlands and abroad. Sidney's fields of expertise include vice, homicide and drug related offences. Sidney has written extensively about the Dutch legal system and published a book as historian about the events surrounding the Kristallnacht (1938). He is well known for his strong opinions on human rights issues in general and LGBTQ rights in particular. Aside from being a criminal defence lawyer, he also provides legal assistance to victims of hate crimes.
Marianne Lochs started working as a criminal defence lawyer for Spong Attorneys in 2010, after graduating with honors in law and criminology at Leiden University. During her studies she worked as a clerk at the Administrative High Court (Centrale Raad van Beroep) and the District Court of The Hague. Marianne Lochs provides assistance in a wide range of criminal cases and has extensive experience in cases relating to trafficking in human beings, murder and manslaughter and other violent crime. In December 2019 she obtained a PhD at Leiden University on the subject of contempt of court. As a member of the Advisory Committee on Criminal Matters of the Netherlands Bar, she also advises on new legislation in the field of criminal law.
Bernard Sprenger started working as a criminal defence lawyer for Spong Attorneysin February 2016. He holds a bachelor's degree from Utrecht University and a masters degree in criminal law from the University of Amsterdam. Sprenger can be characterized as an enthusiastic defence lawyer with a sharp eye for the position and the interests of his clients. His work focus is on the general criminal practice.
Stijn Peerik joined Spong Advocaten in June 2019. He specialized in criminal law and procedure at the University of Amsterdam. During his studies he also worked for seven months as full-time intern at the office of the public prosecutor in The Hague and Amsterdam. This background strengthened his ability to analyse and defend the interests of clients in criminal cases.
Dané Kisteman works at Spong Advocaten since January 2020. Dané studied law at the University of Groningen where she obtained a so-called "togamaster" in criminal law. A togamaster is a master in which internships play an important role and in which a lot of attention is given to written and oral communication skills. During her studies, Kisteman worked as an intern at Spong Advocaten as well as at the public prosecution office at the court of appeal for the Arnhem-Leeuwarden region, first as an intern and later as a law clerk. Her studies, internships and work experience have enabled her to clearly identify the key points in building up a defence.