Forbidden Peak Death

Anyone know details about this incident? 

https://www.mountaineers.org/blog/remembering-mountaineer-sue-bennett

I read somewhere that it was a rappelling accident, but no other details.

EDIT: 

Park officials believe Bennett was rappelling when she fell.

“She lost control and wound up slipping off the end of the rope,” said Denise Shultz, chief of Interpretation and Education at North Cascades National Park.

http://www.seattletimes.com/seattle-news/bellingham-climber-dies-after-falling-into-crevasse-on-forbidden-peak/

Thanks Gavin. Guessing no stopper knot then. Or it failed.