|Death cause:||Suicide by cyanide capsule|
|Appears in:||Trojan Horse|
Richard Lesser was a computer programmer who, under the pretence of wanting to cut a deal to save himself from Hasan was brought back to the Los Angeles Counter Terrorist Unit. Once there, he unleashed a "Trojan Horse" virus, corrupting CTU's computer systems.
Lesser, along with his bodyguard Cole Keegan, first appeared in a hotel Tijuana, Mexico in the room where Tony Almeida and Fay Hubley were staying. They met with Milo Pressman. It was revealed that he and Lesser were old rivals. After Milo and Keegan rescued Tony from Chechens who were torturing him, Lesser, Keegan and a woman named Brandy, actually an undercover FBI agent journeyed back to CTU.
Once there, Lesser managed to unleash his virus. He revealed that he had been converted by Hasan. Finally, when faced with imprisonment, he committed suicide by swallowing a cyanide capsule in one of his shirt buttons.
Before Day 1