It was penned by the editor (no less) of The Church Today in April 2009. See page 5 of this pdf:
It was easy to track down with Google by inputting that 600,000 claim – and no surprise to see it accompanied by the term “pier review” !
PS: I omitted to mention that it’s a local (Louisiana-based) periodical, and that the article in question was prefaced with this hat tip – if one can so dignify it:
“Editor’s Note: The following information is from a Lighthouse Catholic Media CD titled “The Passion of Christ in Light of the Holy Shroud of Turin,” by Fr.Francis Peffley.”
Well guess what: you can listen to the first eight minutes of the CD without buying it or an MP3 version. Just CLICK HERE or on the image above. Pour a tall one and sit back. Find the player button and listen. The level of inaccuracy is extraordinary.