A federal grand jury in Pittsburgh has indicted three Chinese nationals on charges of computer hacking for allegedly penetrating networks used by Moody’s Analytics and other U.S. businesses to steal sensitive information and communications.

According to the indictment unsealed Monday, the three individuals — Wu Yingzhuo, Dong Hao and Xia Lei — are all owners, employees or associates of a Chinese cybersecurity company called Boyusec.

Beginning in at least 2013, the defendants “and others known and unknown to the grand jury” used spearphishing emails containing malicious attachments or customized malware to hack into networks used by U.S. and foreign businesses, according to the indictment.

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Their targets included Moody’s, Trimble Inc. and Siemens AG, the latter of which has offices in Pittsburg. The hackers allegedly stole roughly 407 gigabytes of data from Siemens’s network in 2015.

“Once again, the Justice Department and the FBI have demonstrated that hackers around the world who are seeking to steal our companies’ most sensitive and valuable information can and will be exposed and held accountable,” acting Assistant Attorney General for National Security Dana Boente said in a statement announcing the charges Monday afternoon.

“The Justice Department is committed to pursuing the arrest and prosecution of these hackers, no matter how long it takes, and we have a long memory,” Boente said.

The Chinese nationals face charges of computer hacking, theft of trade secrets, conspiracy and identity theft.

The indictment was filed in the U.S. District Court for the Western District of Pennsylvania in mid-September and unsealed on Monday.

The revelation comes just days after federal prosecutors in New York unveiled charges against an Iranian computer hacker accused of breaching HBO servers and stealing information about unaired episodes of shows including the hit program “Game of Thrones.”