BRIGHTON, England (AP) – A case in which British police seized hundreds of thousands of dollars allegedly meant to finance a plot to kill the then Saudi Crown Prince Abdullah illustrates the challenges facing efforts to combat terrorist groups, a British security officer said.

At Britain’s first national counterterrorism conference, Detective Superintendent Mark Holmes, head of the country’s National Terrorist Financial Investigation Unit, discussed that 2003 incident and other cases to outline the many ways that terrorists fund their operations.

The previously reported Saudi case started when officers caught a man as he tried to smuggle more than $330,000 in cash through Heathrow Airport on a flight from the United States to Syria in August 2003, Holmes said. He said police confiscated the money but freed the man, later identified as naturalized American citizen Abdurahman Alamoudi, a Muslim activist. They said they later learned he intended to give the cash to Saudi dissidents to help fund plans to kill Crown Prince Abdullah, who became the Saudi king in August 2005. “We suspect this was going to be used to facilitate the murder of Crown Prince Abdullah,” Holmes said Wednesday, not elaborating on details of how the assassination would be carried out.

After the initial discovery of cash, British investigators found another $70,000 that Alamoudi allegedly gave to an individual in London. Police said that person did not know what the money was intended for.

Alamoudi was arrested in September 2003 at Dulles International Airport in Virginia and later sentenced to a 23-year prison term for illegal business dealings with Libya.

Holmes said British police had provided information that helped U.S. investigators build their case against Alamoudi, founder of the American Muslim Council.