There's an FBI affidavit linked in another comment that mentions a search warrant found additional copies of the data at his home, and that he'd been in regular

There's an FBI affidavit linked in another comment that mentions a search warrant found additional copies of the data at his home, and that he'd been in regular contact with a Chinese competitor, who offered him a job and ~$60k US signing bonus based on vaguely phrased information already provided.