Rafael Perez Marin
C# / Delphi / VBA / SQL Developer | Audit & Data Analytics | CISA Certified IT Auditor
Colombia and Remote | linkedin.com/in/rafaelperezm/
Professional resume
Programmer (since age 12) and Data Analysis and SQL Specialist with 17+ years of experience in the design
and implementation of automated analytics solutions that transform manual processes into continuous
monitoring systems. Expert in developing complex ETL architectures, optimizing SQL queries, and creating data
pipelines that process millions of transactions. Experience in reducing analysis time by 98% (from 6 hours to 15
minutes), freeing up over 1,200 hours annually through automation. Developer of an analytical add-in for Excel
(over 45,000 lines of code in C#), continuous auditing systems, and data analytics in Access and SQL Server,
with an ability to detect over $1.7 million in financial irregularities. Certified CISA with expertise in C# .NET,
Delphi, VBA, SQL Server, Oracle, Firebird, SAP S/4HANA, ACL Analytics, and statistical anomaly detection
techniques.
Professional Certifications and Qualifications
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CISA: Certified Information Systems Auditor. ISACA. July 2009. CISA #-.
Foundational C# con Microsoft. FreeCodeCamp. October 2025. Certificate.
Education
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Diploma in SAP S/4HANA Management Consulting. ICESI University, Colombia, endorsed by Chicó
University, California, USA, and Brandenburg University of Applied Sciences, Germany. March 2025.
Diploma in Project Management. TEC Monterrey, Mexico. 2016.
Bachelor of Science in Public Accounting. University of Zulia, Venezuela-. Registered
Accountant No. 47,315.
Native Spanish speaker and advanced English (B2/C1).
Skill Summary
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Databases and SQL: SQL Server -, Stored procedures, query optimization, execution plans,
indexes) | Oracle Database (Linked servers from MSSQL, enterprise data extraction) | SQL (Complex queries,
Common Table Expressions (CTEs), window functions, multilevel joins) | SQLite | Firebird/SQL.
Programming Languages: C# .NET (Visual Studio, .NET Framework 4.8) | VBA/VBScript: Automation of
extraction and analysis processes | ACL (Audit Command Language): 438+ data analysis scripts developed
| Delphi | Microsoft Access | T-SQL | Object-Oriented Programming (OOP).
Data Analysis Tools: ACL Analytics / Arbutus | Microsoft Access | Advanced Excel | SQL Server Reporting
Services (SSRS).
Advanced Analysis Techniques: Fraud detection (Benford's Law, Pareto Analysis, Z-Score, Gestalt
Element Link) Statistical analysis (MUS/MMA sampling, random sampling, stratification) | Anomaly
detection (identification of duplicates, outliers, unusual patterns) | Big data analysis (processing 2 million+
transactions).
Project Management: Project Management | Agile Methodologies | Scrum.
Risk and data analysis: Data analysis lifecycle management | Data visualization | Continuous auditing | Audit
analysis and reporting (ACL, Arbutus, SQL Server Reporting).
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Rafael Perez Marin | C# / Delphi / VBA / SQL Developer | Audit & Data Analytics | CISA Certified IT Auditor
Working Experience
INDEPENDENT DEVELOPER AND IT AUDIT CONSULTANT | REMOTE
05/2025 – Current Date
Currently developing a C# .NET email forensics solution using machine learning techniques, implemented in C#
without third-party libraries, for ethics hotline and fraud investigations. Developed Microsoft Office add-ins
using Visual Studio 2017, C# .NET, and Add-In Express, including analytical software for Excel (CAATAnalytics,
45,000 lines in C#), PowerPoint (ShowPoint, 9,400+ lines in C#), and Word (TyperTools, 10,300+ lines in C#).
Designed and delivered technical courses on SQL Server database auditing for ISACA Latin America chapters.
ACTIVE CAREER BREAK | REMOTE
03/2025 – 04/2025
Part of a staff reduction due to restructuring following a change in company strategy. Full-time caregiver and
home manager, maintaining connections within the audit and IT sectors. Proactively seeking professional
development and certifications through online courses.
IT INTERNAL AUDITOR
04/2022 – 02/2025
CAMPOSOL COLOMBIA S.A.S., Pereira, Colombia
Designed and implemented continuous auditing of SAP S/4HANA for the procurement process using ACL
Analytics. The solution was based on 438 scripts in ACL and Microsoft Access/VBA to analyze 27,500 monthly
purchase transactions and authorization objects across more than 150 SAP tables.
INDEPENDENT DEVELOPER AND IT AUDIT CONSULTANT | REMOTE
11/2010 – 11/2021
Developed T-SQL scripts to automate auditing processes in SQL Server 2005 to 2012 for analyzing user security,
backup execution, object modification, and data privacy. I currently use these scripts in my SQL Server database
auditing courses (updated to SQL Server 2019). Developed scripts to automate user security analysis in Active
Directory using VBScript, Microsoft Access, and ACLs. These scripts identify users without passwords, inactive
users, users with high privileges, former employees, and other similar situations. Developed a data analysis
project to detect inaccurate and non-compliant taxpayers in Colombian municipalities' tax returns and to
implement tax audit software in Colombian market
PRINCIPAL IT AUDITOR
06/2014 – 09/2018
CAF Latin America Development Bank, Caracas, Venezuela
Developed an automated audit system in SQL Server 2012 for financial and payroll processes (7 countries, 700
employees), generating 15 SSRS reports and achieving 30% operational savings in travel expenses and user
profile security reviews. This involved integrating information from various SQL Server 2000, 2005, 2008, and
2012 databases, using SQL Server and custom C# .NET developments to compensate for the lack of SSIS, with
query optimization based on indexes and CTEs.
INFORMATION SYSTEMS AUDITOR
07/2013 – 06/2014
MAPFRE La Seguridad, Caracas, Venezuela
Developed a fraud analysis prototype in SQL Server 2008, extracting data from Oracle and applying business
rules to trigger alerts to the fraud department to initiate investigations. Developed scripts to automate user
security analysis in Active Directory using VBScript, Microsoft Access, and ACLs, identifying users without
passwords, inactive users, high-privilege users, active users of former employees, among other audit and
security tests. Developed T-SQL scripts to automate audit processes in SQL Server 2005 to 2012 for analyzing
user security, running backups, modifying objects, and ensuring data privacy. I currently use these scripts in my
SQL Server database auditing courses (updated to SQL Server 2019).
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Rafael Perez Marin | C# / Delphi / VBA / SQL Developer | Audit & Data Analytics | CISA Certified IT Auditor
INFORMATION SYSTEMS AUDITOR
12/2011 – 06/2013
BFC Banco Fondo Común, Caracas, Venezuela
Automated daily cash reconciliation across 165 branches and 230 ATMs, developed in SQL Server 2008, SSRS,
and C# .NET (to compensate for the lack of SSIS). This optimized the process, reducing reconciliation time from
6 hours to 15 minutes using SQL Server and .NET.
INDEPENDENT DEVELOPER
01/2008 – 12/2011
Developed marketing software for sending SMS messages via GSM and CDMA phones from a PC using C#.NET
in Visual Studio 2008 and a Firebird/SQL database in 2011.
ADVISORY SERVICES SENIOR CONSULTANT
07/2008 – 11/2010
ERNST & YOUNG VENEZUELA (represented by Mendoza, Delgado, Labrador & Asociados).
Developed a reconciliation process in ACL (Audit Command Language) and Microsoft Access/VBA for over 2
million POS transactions (US$1.4 billion detected), and implemented payroll analysis for 3,000 employees using
ACL, Microsoft Access/VBA, and Excel.
ENTERPRISE RISK SERVICES SENIOR CONSULTANT
04/2002 – 07/2008
DELOITTE VENEZUELA (represented by Lara Marambio & Asociados)
Developed data analysis processes to validate $60 million in loans and $80 million in savings accounts (74,000
monthly transactions) and insurance reserves using ACL and Access/SQL tools for financial institutions. I
participated in the quality review of a national currency conversion for a telecommunications company.
Implemented a payroll analysis support system in ACL, Microsoft Access/VBA, and Excel for the financial audit
of a bank with 700 employees on payroll, to verify payroll, labor and parafiscal liabilities calculation.
INDEPENDENT DEVELOPER
Up to 2002
Developed an add-in for Excel 97 using Visual Basic for Applications (VBA) to facilitate the preparation and
editing of working papers for auditing firm staff.
Developed software in Delphi 6.0 for analyzing and measuring failures, losses, and damages in pharmaceutical
inventories to support the implementation of a quality management process at Comercial Belloso (COBECA) in
Maracaibo, Venezuela.
Designed, developed, and populated (data-entered) a student grade database in Access 97 for Simón Rodríguez
University (Venezuela) to digitize the academic records of students in the Business Administration programs.
Designed and developed an Access 97 database to manage intercompany accounts and the health insurance
coverage for employees of the Central Bank of Venezuela, Maracaibo Branch.
Developed student schedule creation software in Delphi 4.0 for the Student Center of FACES, Faculty of
Economic and Social Sciences, University of Zulia, Venezuela.
Developed music scheduling software in Visual Basic 3.0, and commercial scheduling software in Delphi 4.0 for
radio stations Reloj 93.5 FM and Sabor 106.5 FM in Maracaibo, Zulia State, Venezuela.
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