https://www.sandia.gov/labnews/2021/09/10/remembering-9-11-at-sandia/
http://archive.today/2021.12.29-201045/https://www.nytimes.com/2006/02/02/politics/new-team-plans-to-identify-nuclear-attackers.html
https://www.nytimes.com/2006/02/02/politics/new-team-plans-to-identify-nuclear-attackers.html
Mr. Evenson said a secret presidential directive, "National Strategy to Combat Weapons of Mass Destruction," signed in September 2002, called for forming the team and its supporting network, which includes the Defense Department and other agencies.
The goal, he said, was "to figure out who attacked us" by analyzing the origins of nuclear materials and the origins and design of the devices.
reference:
https://irp.fas.org/offdocs/nspd/nspd-17.html
NSPD-17 / HSPD 4 [unclassified version]:
National Strategy to Combat Weapons of Mass Destruction
December 2002
https://www.globalsecurity.org/military/library/congress/2001_hr/010425cpr.pdf
Statement of C. Paul Robinson, Director
Sandia National Laboratories
United States Senate
Committee on Armed Services
Strategic Subcommittee
April 25, 2001