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Our Team

At Z&A Law, our strength lies in the experience, discipline, and strategic focus of our team. Leading our practice is Juan Antonio Lozada, a seasoned trial attorney whose insight, courtroom command, and structured approach to litigation have earned the trust of insurers and corporate clients across multiple states. Our attorneys and paralegals bring together deep litigation experience, multilingual capabilities, and a shared commitment to disciplined case management and efficient defense. Whether navigating complex insurance disputes or coordinating multi-jurisdictional claims, Z&A’s team operates with precision, business awareness, and procedural control — delivering measurable results while protecting our clients’ positions and reducing exposure.

Juan Antonio Lozada Leoni

Partner | Managing Attorney | Insurance Defense & Civil Litigation

Accomplished trial attorney and senior business leader with 20+ years of experience across state, federal, and military courts, as well as Fortune 500 companies and complex civil litigation practices. Proven record of dozens of jury trials as prosecutor, insurance defense counsel, and senior trial attorney in construction defect litigation. Recognized for corporate leadership, strategic risk management, and team development. Successfully completed executive education programs at Wharton, Frankfurt School of Finance & Management, and WHU – Otto Beisheim School of Management.

Core Competencies:

  • Jury Trials & Litigation Strategy
  • Insurance Defense & Coverage Disputes
  • Construction Defect Litigation
  • Corporate Leadership & Risk Management
  • Business Strategy & Regulatory Compliance
  • Team Development & Mentorship

Professional Experience:

Managing Attorney – Civil Litigation Practice
Private Practice, Texas & Colorado | 2017 – Present

  • Founded and managed firms specializing in complex civil, insurance, and commercial litigation.
  • Supervised trial teams and coordinated litigation strategies across multiple jurisdictions.

Senior Manager – U.S. AML Compliance
MoneyGram International, Dallas, TX | Oct 2016 – Apr 2017

  • Directed compliance operations across 30+ countries.
  • Managed federal regulatory inquiries and risk mitigation strategies.
  • Oversaw multi-million-dollar compliance initiatives in collaboration with executives.

Trial Attorney – Liberty Mutual Insurance
Houston, TX | Jun 2015 – Oct 2016

  • Represented Liberty Mutual in personal injury and insurance coverage disputes.
  • Successfully tried multiple jury cases to verdict with favorable outcomes.
  • Directed all phases of litigation, including discovery, motions, and appeals.

Senior Trial Attorney – Construction Defect Litigation
Boutique Law Firm, Colorado & Texas

  • Managed high-value construction defect cases for developers, contractors, and insurers.
  • Conducted jury/bench trials, depositions, and settlement negotiations.
  • Collaborated with expert witnesses to shape liability and damages strategies. Prosecutor & Senior Trial Counsel – U.S. Army JAG Corps, DOJ & State of Texas | 2005 – 2016
  • Served as lead counsel in dozens of jury trials, including violent crimes, fraud, and complex litigation.
  • Provided legal guidance to senior military leaders on regulatory and operational matters.
  • Prosecuted state crimes as Assistant District Attorney in Livingston, Texas.
Juan Antonio Lozada

Education & Executive Training:

  • Executive MBA, Frankfurt School of Finance & Management, Expected 2025
  • Advanced Management for Senior Leaders Program, WHU – Otto Beisheim School of Management, 2025
  • General Management Program (GMP), The Wharton School, University of Pennsylvania, 202
  • J.D., The Ohio State University Moritz College of Law
  • LL.M., University of Texas at Austin (International Public Law)
  • LL.M., University of Houston (Private Law)
  • LL.M., American University (Human Rights & Humanitarian Law)
  • M.A., International Relations, St. Mary’s University
  • B.A., Latin American Studies, University of Texas at Austin

Bar Admissions & Certifications:

  • Texas Bar (Active)
  • Colorado Bar (Active)
  • Certified Anti-Money Laundering Specialist (CAMS)

Legal Team

Andrés Arteaga

Chief Technology Officer (CTO)

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Vanessa Siso

Executive Operations Associate | Office of the CEO
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Jonathan P. Shultz

Senior Associate
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Elsa Calderon

Senior Paralegal

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Andrea Castellanos

 Paralegal

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Mariel Lucien

Paralegal

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Vannesa Rodriguez

Paralegal
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Professional Profile

Andrés Arteaga serves as Chief Technology Officer (CTO) of Zupkus & Angell, P.C., bringing extensive experience leading technology transformation, operational continuity, and infrastructure modernization for law firms in growth and organizational transition environments.

He has a strong background in implementing legal technology platforms, automating internal processes, supporting remote legal teams, and leading technology integration projects, with a particular focus on operational efficiency, information security, and scalable systems.

His profile combines strategic leadership, advanced technical expertise, and a deep understanding of the operational needs of U.S.-based law firms.

Selected Experience

Zupkus & Angell, P.C. – Chief of Technology / Interim Firm Administrator
Remote | July 2025 – December 2025

  • Led the firm’s technology operations and administrative continuity during the ownership transition.
  • Served as a key member of the incoming ownership leadership team, ensuring secure data transfers and uninterrupted business operations.
  • Coordinated critical integration projects, including system audits, vendor negotiations, and internal process redesign.
  • Drove the alignment of technology infrastructure and administrative processes with new organizational standards.

Law Firm Tech Consulting (LFTC) – Senior .NET Developer / Partner
Remote | November 2022 – Present

  • Member of the leadership team and co-founder of a legal technology software initiative designed for small and mid-sized law firms.
  • Responsible for feature planning, full-stack development, and technology support for U.S.-based legal clients.

The Law Office of Juan Antonio Lozada, PLLC – IT Department Implementation / IT Analyst
Remote | 2022

  • Led data migration and digital platform consolidation initiatives.
  • Identified and optimized technology-related operating costs.
  • Provided technical support for a remote legal team of more than 45 staff members and delivered onboarding training for new employees.

Education

Bachelor’s Degree in Mechatronics Engineering
Universidad Internacional del Ecuador (UIDE)

Areas of Expertise

  • Law firm technology strategy
  • Digital transformation and process automation
  • Infrastructure management, security, and cloud platforms
  • Systems integration and data migration
  • Technology project leadership in legal environments

Technical Skills

.NET (C#), SQL, Python, Linux, networking, Microsoft 365, and legal technology solution architecture.

Vanessa Siso is an accomplished operations professional with extensive experience supporting executive leadership, managing complex administrative workflows, and optimizing cross-departmental processes in remote environments. Known for her proactive approach, exceptional organization skills, and ability to maintain structure in fast-paced legal operations, she ensures that attorneys and firm leadership receive the strategic support needed to operate efficiently and stay focused on client outcomes.

Her background includes executive support, legal operations coordination, documentation management, team supervision, training, and process optimization—making her a reliable bridge between departments and a key contributor to firm productivity and compliance.

Professional Experience

Executive Operations Associate / Chief of Staff – CEO Office

The Law Office of Juan Antonio Lozada | Remote (June 2025 – Present)
Vanessa provides high-level operational and administrative support to the CEO and partners, ensuring seamless day-to-day functionality within the firm. Her responsibilities include managing complex calendars and meetings, organizing documentation for firm operations, loan applications, and multi-state bar admissions, and coordinating cross-departmental initiatives. She implements organizational systems that improve efficiency and strengthen compliance across legal and administrative processes.

Bootcamp Coordinator

BaseLang | Remote (July 2021 – June 2025)
Supported the program manager, developed administrative materials, handled exclusive customer service for program participants, trained new instructors, monitored program requirements, managed statistics and performance data, and oversaw payment verification and follow-up.

Elite Coordinator

BaseLang | Remote (November 2019 – June 2021)
Created and optimized program documentation, provided dedicated client service, trained new teachers, managed payment workflows, and supported administrative processes for the Elite program.

Senior Coordinator

BaseLang | Remote (October 2018 – October 2019)
Oversaw and supported a team of teachers, managed administrative matters related to her team, developed automation projects to improve student progress, provided customer service, and assisted with onboarding of new instructors for the Bootcamp program.

Spanish Teacher

BaseLang | Remote (June 2018 – September 2018)
Provided online Spanish instruction to students around the world.

Construction Supervisor / Architect – Various Firms (2004 – 2017)

Vanessa previously worked in architecture and construction supervision for multiple firms in Venezuela, managing contractors, updating plans and documentation, supporting design projects, preparing cost estimates, and handling long-term project planning. This experience strengthened her analytical skills, documentation rigor, and ability to coordinate large multidisciplinary teams—skills she now applies to legal operations.

Education

Architect
Universidad Central de Venezuela – Caracas, Venezuela (June 2003)

Jonathan P. Shultz is a Colorado attorney with more than fifteen years of practice spanning consumer bankruptcy, probate, and civil matters. He also brings the perspective of someone who built and ran his own firm, where every client relationship, every filing, and every deadline rested on him alone.

For over a decade, Jonathan owned and operated The Law Offices of Jonathan P. Shultz, LLC in Denver, guiding more than 500 individuals and families through Chapter 7 and Chapter 13 proceedings. Many of those former clients continue to send referrals years later, a reflection of the trust he builds with people who come to him during difficult financial moments.

Profile

Jonathan’s path to the practice of law was deliberate. He earned a paralegal certificate in 1994 and worked in the field before completing his business degree at the University of Colorado Denver and, later, his Juris Doctor at the University of Denver Sturm College of Law. During law school he clerked at Nicholls Nicholls Biles & Bower, drafting bankruptcy pleadings for a Chapter 7 Panel Trustee. He filed his first Chapter 7 case as a student lawyer under the supervision of his mentor, Trustee Jon Nicholls, a relationship that began through the DU Mentoring Program and Metro Volunteer Lawyers.

He went on to handle the majority of the bankruptcy caseload at Webb & Schtul, LLC, assisting lead counsel with litigation and gaining courtroom and trial experience, before launching his own practice in 2011.

More recently, Jonathan expanded into probate and family matters at Patricia Jo Stone, P.C., where he assumed the caseload of a retiring associate. There he represented clients in probate litigation, guardianship and conservatorship, family law, and protection order hearings, including regular court appearances. He has also handled landlord/tenant and eviction matters in Colorado county courts, along with collections and HOA files.

Jonathan works with clients across Colorado, bringing a practical, client-first approach shaped by years of direct, one-on-one representation.

Education

  • Juris Doctor, University of Denver Sturm College of Law, Denver, CO (2006)
  • Bachelor of Science in Business and Administration, Management Emphasis, University of Colorado Denver (2000)
  • Paralegal Certificate, Denver Paralegal Institute, Denver, CO (1994)

Bar Admissions

  • Member, Colorado Bar

Professional Background

  • Associate, Patricia Jo Stone, P.C., Parker, CO
  • Founder and Sole Owner, The Law Offices of Jonathan P. Shultz, LLC, Denver, CO
  • Associate, Webb & Schtul, LLC, Denver, CO
  • Law Clerk, Nicholls Nicholls Biles & Bower, Denver, CO
  • Contract attorney engagements through Adams & Martin Group, Denver, CO

Community Involvement

  • Jonathan’s early career was shaped by Denver’s pro bono and mentorship networks, including Metro Volunteer Lawyers and the University of Denver Mentoring Program.

Beyond the practice

  • Jonathan spends his free time with his family, hiking Colorado’s trails, and staying active.