Emails obtained by Motherboard also reveal new details about previously unreported NSO Group products.
The move comes after Motherboard found the U.S. branch of NSO Group pitched hacking tech to American police.
A brochure and emails obtained by Motherboard show how Westbridge, the U.S. arm of NSO, wanted U.S. cops to buy a tool called Phantom.
Emails between the DEA and NSO obtained by Motherboard explain why the DEA didn't purchase the company's malware in 2014.
NSO Group's products have been linked to hacking attempts on journalists, activists, and dissidents.