The article mentions that Schatten first visited Hwang's Seoul lab in 2003 according to Dr. Snyder of the Burnham Institute. One notes that the priority documents for both the Schatten and Hwang patent applications were filed in 2003.
The Guterman article states:
It was Mr. Schatten's severing of his collaboration with Dr. Hwang -- despite the close relationship between them -- that helped spark investigations of the Korean research. Some American researchers praise Mr. Schatten as "basically a whistle-blower," says William R. Brinkley, senior vice president for graduate sciences at Baylor College of Medicine, who has known Mr. Schatten for decades.
Sadly, I have to take issue with this assertion. Blog posts about problems with the 2005 Science paper appeared within weeks after the electronic publication (May 2005), which is months before Schatten severed relations. Further, Schatten was probably aware of the investigations by Korean television (MBC, "PD Notebook"). Thus, it is more likely that Korean complaints about Hwang's research sparked Schatten's actions in November 2005, not the other way around. The Korean investigations by MBC went far beyond the problem of unethical (and under Korean law after Jan. 2005) illegal acquisition of eggs.