"That was a lie, right? Baum asked.
"Of course," Foto responded, acknowledging that Valle had been under investigation for only a few weeks. He said the ruse was investigative technique aimed at getting the defendant to speak.
The testimony came on a day when the government was seeking to show jurors Internet images of dead and dismembered people.
Defense lawyers are opposing the presentation of as many as 34 ghastly exhibits of images the government says it took from Valle's computer.
U.S. District Judge Paul Gardephe has not yet decided if jurors will see the pictures that defense lawyers say may have been saved on the officer's computer automatically without him ever seeing them when he went on certain websites.
The government says the exhibits include a picture of a dead body with feet unattached, an image Valle's wife testified she saw when she went to one of his favorite sites and discovered why he stayed up late online.
Valle has been held without bail since his October arrest. Throughout the trial, which began Monday, Valle's lawyers have attacked government evidence as nothing more than the reflection of a man engaging in extreme sexual fantasies with like-minded people around the world. The government has conceded that Valle never met the purported Internet co-conspirators and no women were harmed.
Jurors have heard testimony from Valle's estranged wife and from former classmates and other women who testified they knew Valle on a casual basis and never considered him dangerous. Their testimony was followed by evidence that all of them were the subjects of emails and chats describing how they could be snatched away and eaten.