Smoke & Mirrors (S06E14)

When Sen. Kinsey is assassinated in broad daylight in front of a dozen civilian witnesses, Col. Jack O'Neill is the prime suspect, having been seen and videotaped leaving the scene with a rifle in hand. And O'Neill's distaste for Kinsey, who had tried more than once to take down Stargate Command in order to control it, is well-known. O'Neill's alibi, that he was alone on vacation fishing, is compromised when the murder weapon is found dumped in the lake near O'Neill's vacation cabin. Confronted with such damning evidence, Gen. Hammond has no choice but to place O'Neill under arrest and then remand him to the civilian authorities in Washington. Because the president, for political reasons, is unable to intervene on O'Neill's behalf, Gen. Hammond suspends SG-1's offworld duties and assigns Maj. Samantha Carter, Teal'c and Jonas Quinn to investigate the mystery and clear O'Neill. Maj. Carter surmises there was only one way someone could have impersonated the colonel so precisely: Three years ago, aliens tried to take over Stargate Command using mimic devices that could camouflage them to look like SGC personnel. After the situation was defused, SGC recovered 12 of the mimic devices, each programmed to impersonate a specific person. One of them had been made to mimic Col. O'Neill. SG-1 discovers that the mimic devices, under guard at Area 51, have been replaced with fakes. Carter has Teal'c and Jonas go through the personnel files of everyone who had access to the devices, while she goes to Washington to see Malcolm Barrett, a friend in the government's covert National Intelligence Division (NID). Barrett tells Carter about an even more shadowy organization operating deep within the NID, and he reveals that he had blackmailed Sen. Kinsey into working with him to expose this splinter group. Unfortunately, that group got to the senator first. Barrett then takes Carter to an illegal arms dealer who had sold the murder weapon to Col. O'Neill's double. There they find another gun that the shooter had handled, and Barrett has it checked it for fingerprints. They are not O'Neill's. They belong to an NID agent named Mark Devlin. Carter and Barrett pay Devlin a visit, but his house blows up — a trap. They barely escape.

Meanwhile, Teal'c and Jonas have narrowed the number of suspects with access to the mimic devices down to one Dr. Langham, who was supposed to have died in a car crash. Jonas and Teal'c track down Dr. Langham and take him into custody at Stargate Command, where he confesses to stealing the mimic devices and delivering them to the NID splinter group, The Committee. The group's objective is to take the alien technology that SGC has collected and use it for monetary gain, and they will kill anyone in their way — even a U.S. senator. Dr. Langham gives Hammond the group-members' names in return for relocation to another world via the stargate. Maj. Carter decides to trust Agent Barrett with the intel on the mimic devices. He, in turn, trusts her with the fact that the senator is not dead but in a coma, under 24-hour guard, and that a Maj. Davis from the Pentagon is on his way there. But Davis is actually Agent Devlin, camouflaged as Davis so that he can kill the senator "again." After completing his mission, Devlin reports back to The Committee, who instruct him to next threaten Gen. Hammond's family and, if Hammond remains unintimidated, to kill him. Just then, Agent Devlin morphs into Maj. Carter — who had used one of SGC's mimic prototypes to create a subterfuge and get the proof she needs to clear O'Neill. Carter and Barrett had apprehended Devlin earlier, and Carter had taken his place. Agent Barrett comes bursting in with his agents and takes The Committee into custody. Kinsey makes a full recovery and exonerates O'Neill in public, which, to O'Neill's displeasure, will ironically help get Kinsey elected president. (Metro-Goldwyn-Mayer (MGM))