Russian government hackers have attacked the Democrat National Committee (DNC) and stole their research on presumptive GOP presidential candidate Donald Trump.

The attack went on for over a year.

DNC officials and security experts said the hackers read emails and chat traffic. They believe they did not gain access to donor’s private information, leading them to call it “traditional espionage” and not “criminal hackers.” From The Washington Post:

“It’s the job of every foreign intelligence service to collect intelligence against their adversaries,” said Shawn Henry, president of CrowdStrike, the cyber firm called in to handle the DNC breach and a former head of the FBI’s cyber division. He noted that it is extremely difficult for a civilian organization to protect itself from a skilled and determined state such as Russia.

“We’re perceived as an adversary of Russia,” he said. “Their job when they wake up every day is to gather intelligence against the policies, practices and strategies of the U.S. government. There are a variety of ways. [Hacking] is one of the more valuable because it gives you a treasure trove of information.”

In late April, CEO Amy Dacey’s operations chief told her that “their technology team had noticed some unusual network activity.” Dacey called lawyer Michael Sussmann, who then asked Henry to install software to find the hackers:

The firm identified two separate hacker groups, both working for the Russian government, that had infiltrated the network, said Dmitri Alperovitch, CrowdStrike co-founder and chief technology officer. The firm had analyzed other breaches by both groups over the last two years.

One group, which CrowdStrike had dubbed Cozy Bear, had gained access last summer and was monitoring the DNC’s email and chat communications, Alperovitch said.

The other, which the firm had named Fancy Bear, broke into the network in late April and targeted the opposition research files. It was this breach that set off the alarm. The hackers stole two files, Henry said. And they had access to the computers of the entire research staff — an average of about several dozen on any given day.

Alperovitch also said the two groups did not work together. Fancy Bear has connections to the Russian military service GRU. They do not know for sure about Cozy Bear, but the company believes they might work for “the Federal Security Service or FSB, the country’s powerful security agency, which was once headed by Putin.” The Kremlin called the FSB the KGB during the USSR. No one is shocked that the companies do not work with each other:

The lack of coordination is not unusual, he said. “There’s an amazing adversarial relationship” among the Russian intelligence agencies, Alperovitch said. “We have seen them steal assets from one another, refuse to collaborate. They’re all vying for power, to sell Putin on how good they are.”

Russian hackers targeted the White House, State Department, and Joint Chiefs of Staff in the past. They also hacked into universities in the U.S., Canada, and Asia.

Tensions between Russia and the U.S. continue to elevate since the Kremlin invaded Ukraine and annexed Crimea in 2014. To make matters worse, Russian officials have threatened former Soviet republics, which have forced NATO to bump up security in Eastern Europe. Russia has responded by placing more military close to their border with Ukraine.