Our Team


Lt Col. Keith A. Harper
Founding Partner & Past President of the Counter Threat Institute, International and CTI Protection & Investigation Services, Inc
Lt Col. Harper envisioned CTI as the premier security consulting services corporation to Silicon Valley clients in the areas of: Threat Mitigation, Asset Recovery, Personal Protection, Loss Prevention, Crisis Management, and Reputation Protection. Lt Col. Harper has a Business Management degree from Saint Mary’s College and a graduate degree in Transnational Terrorism Studies. He is a graduate of the 196th session of the FBI National Academy, the Air Command and Staff College, and the Special Investigations Academy in Washington DC. He is a retired military officer, civilian police command officer, and retired US Federal Agent having previously worked with Department of Defense, Justice, and State counterterrorism & counterintelligence agencies, and as an officer on the FBI Joint Terrorism Task Force (JTTF) in Silicon Valley.
Throughout his law enforcement career Lt Col. Harper has been recognized for his support to communities as a child advocate and for his aggressive pursuit of human traffickers. He has extensive operational investigative service in both the government and private sector throughout the United States, Eastern Europe, Africa, and Asia. He has written and lectured extensively on Countering Strategic and Tactical Opposition Doctrine; Counterterrorism Investigations; Child Sexual Abuse Investigations, Victim Advocacy, and Advanced Criminal Investigation to senior government leadership, counter-terrorism officials, and criminal investigation agencies in the US and abroad.



Chief (ret) Winfred Tabarelli
Case Manager
Chief Winfred Tabarelli has over 38 years of experience in the German State Police service. He supervised over 2000 police officers and detectives as the police chief for the state of Schleswig-Holstein, Republic of Germany. During his career, Chief Tabarelli also served as the commander of the Homicide Division and has extensive experience supervising international investigations in drug trafficking, organized crime, white collar crime, special surveillance operations and undercover operations. He served as head for the Crime and Criminology Department at the State Police College, and performed duties to professionalize the police in the Eastern European States after the fall of the iron curtain.
Chief Winfred Tabarelli accepted service with the European Union – EU – in 2000 as a project leader for the European Union in Estonia, Latvia and Lithuania. Developing and implementation of a national and international drug strategy. Expert for Euro-Customs in the Baltic States to develop and implement an organizational structure and a nationwide IT-System for Customs to fight against drug-trafficking. Since 2002, Chief Tabarelli has served as the leader of an International Investigative Task Force. Now he is the Senior Investigative Consultant for CTI International and CTI Europe, conducting investigations and operations throughout Europe, the United States and Southeast Asia against network security intrusions, intellectual property theft, asset recovery operations and other forms of cyber attack. Chief Tabarelli is an Honorary Judge of the High Court for Administration in Germany.



Mr. Guy A. Harper
President and CEO

Mr. Harper is the President and CEO of the Counter Threat Institute International & CTI Protection & Investigation Services Inc. He is also the President of Universal Developing, and Universal Partners Limited and has been in business for over thirty years. Mr. Harper has founded, managed, and led several successful businesses, joint ventures, and investment & construction enterprises that have improved the quality of life of thousands of residents of the San Francisco Bay Area. He is a former municipal law enforcement officer and has provided operational support and investigative assistance to sensitive counter-terrorism operations. Mr. Harper is an expert in construction design, value engineering, infrastructure, and business management. Mr. Harper brings unparalleled business sense and capable leadership to CTI’s management team.


Dr. William  
California State Licensed Private Investigator
Dr. William is an experienced California State Licensed private investigator who has worked a myriad of cases covering the spectrum of the security world. Calling upon his real world experience as a State and Federal law enforcement officer, as well as worldwide contacts, he has crafted solutions to some of the most difficult cases. He has also utilized his international academic expertise to interpret and solve some of the more complex multinational security problems. Formerly he was the Dean of student affairs, and associate Dean of recruitment at Henley-Putnam University. An institution which offers undergraduate and graduate degrees in Intelligence, Counterterrorism and Protection management. In that regard Dr. William has participated in executive decisions that have helped shape the direction of one of the foremost university’s in the high risk security field.
Prior to joining the university, Dr. William was a twenty year veteran of law enforcement. In that capacity he was a criminal investigator with the Santa Clara County District Attorney’s Office, participating in SAFE task force, the nation’s first felony enforcement sexual assault prevention unit. Additionally, as an FBI task force agent, and an expert in fugitive tracking, he served in the violent fugitive task force. He apprehended many high profile criminals, including several international fugitives, as well as one of the US Marshals top ten fugitives. He also was a task force member of the REACT high tech unit. He holds three masters degrees, one in International Relations from San Jose State university, a second in International management from Thunderbird, the Garvin school of international management. His third masters is in political science from the University of Southern California. He also earned a Ph.D in political science, with an emphasis on political violence, from the University of Southern California.


Security Consultant
Joseph is a former Analyst at the Central Intelligence Agency, working in Counter-Intelligence and Counter-Narcotics. He has led high-performance teams for security assessment and protection for clients across the country. He has hands-on experience with security assessments, ethical hacking and security tool development. Joseph has provided to clients network assessments, VoIP assessments, network investigations, computer forensics, cellphone forensics, specialized internet tools and internet tracking and investigations.
Joseph is a nationally recognized speaker on security, converged networks and internet safety. He has spoken across the country on the topics of network security, VoIP security, and Internet Predator tracking. He is the developer of Internet Predator Tracker software for Law Enforcement, and the developer of the only public tools for reporting pedophile and predator websites and emails. He also developed other apps such as; CyberWar App, Android SSHSpy App, Android K-9 Pedophile Reporter version, and Android K-9 Mailsleuth App, PI Camera app, and the Work Diary app.
Joseph has worked with Law Enforcement agencies in order to assist with Computer Crime investigations, some of these include:
o Secret Service (tracing Presidential death threats for AOL)
o Air Force OSI
o US Navy Investigative Service
o NYC Police Dept.
o US Customs
o Local law enforcement from almost all of the 50 states
Joseph’s additional training includes, Certified Information Systems Consultant (CISSP), Certified Cisco Network Associate, Certified Cisco Design Associate , National Security Agency INFOSEC Assessment Methodology, Ethical Hacking, InfoSec Institute Netscreen Certified, Network Associates Intrushield certified, Network Associates ePO certified,Network Associates Entercept certified, Certified Email Tracer, Master Email Tracer, Encase Computer Forensics,Telecommunications Fraud Investigator, Hard drive analysis, Data recovery, & Penetration Testing and Analysis.
Joseph’s many affiliations include:
Federal Agents P.B.A Local 121, Association of Former Intelligence Officers, National Association of Investigative Specialists, & the California Institute of Professional Investigators.
He has written a number of investigative books on technology and Internet based investigations. Currently, he is also teaching classes at the PI Classroom. At the PI Classroom, he trains investigators in the area of technology and internet crime investigations.