Dr Dsouza’s principal research interest is in the theory and philosophy of the criminal law. His doctoral thesis was converted into a monograph titled Rationale-Based Defences in Criminal Law, and published by Hart Publishing in May 2017 (Reviewed in the MLR and Criminal Law & Philosophy). In it, Dr Dsouza suggests a new account of the various types of rationale-based defences in the criminal law, and offers suggestions as to how they should be understood, interpreted, and applied. He has published in peer reviewed journals on topics like the theoretical foundations of consent in the criminal law (Law & Philosophy, 2014; SSRN, 2013), the supposed duty to retreat before using force in self defence (OJLS, 2015), culpability in the criminal law (King’s Law Journal, 2015), accessorial liability (UCL JLJ 2019), and corporate criminal law (Cambridge Law Journal). His latest paper, on the theory of the act-omission distinction in the criminal law won the 2020 award for the Best Paper awarded by the Society of Legal Scholars, and appears in the March 2021 issue of the journal, Legal Studies. Additionally, he has written case comments for the Cambridge Law Review and Archbold Review and his essays on the legitimacy of the death penalty and on artificial intelligence and substantive criminal law have appeared in collections of essays published in 2018 and 2020.  

Dr Dsouza is also keenly interested in the doctrinal law relating to inchoate and accessorial liability. He co-organised a conference in September 2016 which brought together judges of the Supreme Court, representatives of the Law Commission, representatives of the CPS, members of the bar, legal and criminological academic, representatives from the police, campaign groups, and students, to discuss the Supreme Court’s judgement in R v Jogee & Ruddock (2016) and more generally, the law on accessorial liability. In November 2018 he delivered an invited lecture to the Criminal Bar Association's Annual Seminar on 'Developments in Substantive Criminal Law Defences'. He is part of the Criminal Law Reform Now Network's team working on proposing reforms to the law of Consent and Deception. 

Dr Dsouza co-organises the Assize Seminar Series in Cutting Edge Criminal Law. The inaugural seminar was held at Oxford University in May 2017, and further seminars were held at UCL in November 2017, Cambridge in April 2018; Oxford in November 2018; at the Criminal Cases Review Commission in Birmingham in May 2019; UCL in November 2019, and Cambridge in November 2020.