Hackers who stole gigabytes of data from JPMorgan Chase & Co. may have been trying to send a message that U.S. The FBI is investigating the cyberattack on JPMorgan and whether other banks were penetrated in retaliation for U.S.- backed sanctions on Russia, according to people familiar with the investigation who asked not to be identified because the probe is still underway. Keith Alexander, the NSA director from 2005 until last March, said he had no direct knowledge of the attack though it could have been backed by the Russian government in response to sanctions imposed by the U.S.