Stargate SG-1 - Season 4 Episode 5 -

When an SG member tries to assassinate the Tok'Ra leader, it is believed that some of the SGC have been converted into za'tarc - programmed assassins. The Tok'Ra Anise comes to the SGC with Lantash, to try and test the SG members. But the za'tarc detector suggests that O'Neill and Carter are actually za'tarcs. Is this correct and is there another za'tarc at the SGC?