JERRY WATSON WAS DETERMINED to find the truth about Rafid Ahmed Alwan al-Janabi, the Iraqi source codenamed Curveball.

He returned to Baghdad in September 2003 and assembled a small team—two analysts, an operations officer and a few security guys. Their first stop was the home of al-Janabi’s boss at the engineering center where he claimed he had worked until 1999.

“He told us that [al-Janabi] quit in the last few days of 1994. He said he didn’t like the low pay and boring work, and walked out and never returned. So they terminated his employment.

“That told us everything Curveball had said about the mobile plants was a total fabrication. No question. No debate. We had been in Baghdad for two days.”

After finding al-Janabi’s address, photo and college transcripts, they knocked on the gate of his family’s home.

“They said, ‘Of course, come on in.’ He had 10 brothers and sisters, I think.

Served us tea and baklava. Nicest people in the world.”

One of the sisters told them her brother had worked for Babel Film and Television Production, a local company, after he quit the engineering center. At Babel, one of the senior officials remembered him all too well.

“I asked, ‘Was he a good employee?,’” Watson recalled. “He said, ‘No, he stole some equipment and sold it on the black market and cheated us.’ I started laughing. They said they had filed an arrest warrant against him in criminal court.”

They kept investigating. By late September, they had assembled what Watson called “overwhelming evidence, going back 15 years, that Curveball was a fabricator. And [still] no one would believe it.”

His superiors at WINPAC, the CIA center that focused on foreign weapons threats, “did not like the fact we were digging up contradictory and derogatory intelligence on Curveball, and pushing the intel services involved to accept it,” he said. “They wanted us to slow down and be team players in the Iraqi sandbox.”