Fortes, Lopes, Siebner Criminal Law Office
The office
Excellence and personalized service.
Discretion and professional thoroughness.
Since 2020.
Areas of expertise
The firm provides legal advice to its clients in different spheres of activity, both judicially and out-of-court.
In court, in addition to monitoring its clients' cases on a daily basis, the firm has a strong presence in the country's Superior Courts (Superior Court of Justice and Federal Supreme Court).
In out-of-court, the firm provides legal advice and works in the preliminary stages of investigation.
Moreover, it should be noted that the firm represents the interest of its clients in the most varied areas and spheres of Criminal Law.
Criminal law
The Fortes, Lopes, Siebner Advogados works in all stages of the criminal process, from the preliminary stages of the investigation, such as the drawing up of a police report and the monitoring of a police investigation, to representation in court, before ordinary and higher instances.
In addition, it has extensive experience in criminal enforcement.
Economic Criminal Law
The office has a team of expert lawyers, with experience in advising executives of small and large companies throughout the country on issues related to economic, financial, tax, administrative and bidding crimes, as well as asset fraud, money laundering and consumer relations.
Victim Support
Another extremely important activity performed by the office is the support and provision of legal assistance to victims - representation at police stations to issue an occurrence report, follow-up on a police investigation, filing of a criminal complaint, and representation in court as an accusation assistant.
Partners
Founding partner
Guilherme Fortes Bassi
Partner and founder of the firm, he holds a Law degree from the Pontifical Catholic University of São Paulo (PUC-SP) (2014-2018).
Teaching Assistant to Professor Dr. Gustavo Octaviano Diniz Junqueira in the Criminal Law course at the Pontifical Catholic University of São Paulo/SP (2024-).
Member of the Special Compliance Committee and the Standing Environmental Committee of OAB/SP (2025-).
Member of the Institute for the Defense of the Right of Defense (IDDD) (2023-). Part of the IDDD Advocacy Working Group, dedicated to monitoring the development of laws and other regulatory acts that impact the criminal justice system.
Member of the Brazilian Institute of Criminal Sciences (IBCCRIM) (2024-).
Has been part of teams at renowned corporate criminal law firms.
Has experience in the public sector, particularly at the Public Defender’s Office of the State of São Paulo, working mainly in the Jury Court and the Police Inquiry Department.
Founding partner
Lucas Marques Gonçalves Lopes
Partner and founder of the firm, he holds a Law degree from the Pontifical Catholic University of São Paulo (PUC-SP) (2014-2018).
Postgraduate in Human Rights from the Faculty of Law at the University of Coimbra (2020).
Member of the Advanced Studies Group (GEA) in Economic Criminal Law at the Brazilian Institute of Criminal Sciences (IBCCRIM) (2021-2022).
Member of the OAB/SP Permanent Committee on Human Rights (2025-).
Was a member of the Criminal and Penitentiary Policy Committee of the São Paulo Chapter of the Brazilian Bar Association (OAB) (2023–2024).
Has experience in the public sector, particularly at the Public Defender’s Office of the State of São Paulo, working mainly in the Jury Court and the Police Inquiry Department.
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Founding partner
Rubens Siebner Mendes de Almeida
Partner and founder of the firm, he holds a Law degree from the Pontifical Catholic University of São Paulo (PUC-SP) (2014-2018).
Holds a postgraduate degree in Criminal Law and Criminology from the Pontifical Catholic University of Rio Grande do Sul (PUCRS) (2025–2026).
Member of the Institute for the Defense of the Right to Defense (IDDD) (2023-). Joined the Strategic Litigation Department, collaborating with the IDDD on high-impact cases (2025).
Member of the Brazilian Institute of Criminal Sciences (IBCCRIM) (2024-).
Was a member of the Criminal and Penitentiary Policy Committee of the São Paulo Chapter of the Brazilian Bar Association (OAB) (2023–2024).
Participated as a researcher in the Criminal Studies Center at the Pontifical Catholic University of São Paulo (NECrim/PUC-SP) (2016-2018).
Has been part of panels at renowned corporate criminal law firms.
Articles, Interviews and News
Contact
Avenida Marquês de São Vicente, 230, cjs. 601/602, Várzea da Barra Funda, São Paulo/SP, 01139-000
(11) 3392-2253
