From archive.org crawl of a LV Review Journal article the next day:
https://web.archive.org/web/2009021...j_home/1997/Jun-29-Sun-1997/news/5632719.html
[EDIT - short version, people thought they heard gunshots, panic ensued, tables were turned and chips swiped off the tables. Gaming was shut down and secondary chips (still in use) were brought out for the hundreds. This is mentioned in
Bringing Down the House, when one of the MIT blackjack team comes downstairs for their "shift" early in the morning to find only slot machines were running. When all was said and done, there were 19 of these that weren't accounted for when the remainder were sent the chip shredders.]