NEW YORK (AP) — The conviction of an ex-Soviet officer known at the Merchant of Death can be credited in part to the work of a U.S. informant who has made more than $9 million for his undercover work over the past 15 years.Carlos Sagastume (SAG-uh-stooh-mee) was a star witness at the weapons sale trial of Viktor Bout (boot). The federal court trial ended Wednesday with a conviction that could land Bout in prison for the rest of his life.Former federal drug agent Thomas Pasquarello (PAS'-ker-ello) says Sagastume was perfect for the probe that resulted in Bout's 2008 arrest in Thailand. He says a guy like Bout wasn't going to fall for a rookie informant. Still, he says Sagastume might not be finished with his undercover work. He says someone like Sagastume can always reinvent himself.