According to the FBI, a group of Russian hackers who are in no way connected to the Russian government just happened to execute a sophisticated cyber-attack on a variety of Wall Street firms in August, occurring by happy chance just after the U.S. and other Western countries imposed a new round of sanctions on Moscow.

Russian hackers attacked the U.S. financial system in mid-August, infiltrating and stealing data from JPMorgan Chase & Co. (JPM) and at least one other bank, an incident the FBI is investigating as a possible retaliation for government-sponsored sanctions, according to two people familiar with the probe.

The attack resulted in the loss of gigabytes of sensitive data, said the people, who asked not to be identified because the probe is still preliminary. Authorities are investigating whether recent infiltrations of major European banks using a similar vulnerability are also linked to the attack, one of the people said.

According to Bloomberg, “the trail is muddy enough” so that investigators cannot link the attack directly to the Russian government. Security experts told Bloomberg that this is a common tactic which Russian cyber units – an adept force which has crippled whole nations in the recent past – regularly apply.

“The Russians typically keep open the options to do something more, and the question now is what would trigger that and what would our response be?” Strategic Technologies program at the Center for Strategic and International Studies Director James Lewis asked.

Whatever the West’s response, if there is a response, it will be covert. After all, the President of the United States already declared that America’s new conflict with Russia is “not a new Cold War,” and acknowledging the cyber battlefield between these two nations long ago went hot would put the lie to this narrative.

This release from the FBI comes just hours after Ukraine accused Russia of sending a significant number of tanks and troops into its country, signaling a new phase in the hostilities between the two countries. As many commenters have noted, Western governments appear more preoccupied with maintaining the illusion of peace – even a tense peace – between Russia and the West than acknowledging the antagonistic reality relations with Russia.