Clarence Wiedman was the Head of security at Kane Software.
As Head of Security for Kane Software, Wiedman is known to do the less than savory jobs that Jake Kane needed done. It is known that Jake Kane called Wiedman before he reported his daughter's murder, and it was speculated by Veronica Mars that he assisted in the cover-up of Lilly Kane's true time of death by lowering the temperature of her body.
It is known that Wiedman paid Amelia DeLongpre so that her father, Abel Koontz, would falsely confess to the murder of Lilly. When Veronica found Amelia and tried to convince her to reveal the existence of the payoff money, Wiedman got to her first and gave her even more money so that she would leave Neptune ("Kanes and Abel's").
Wiedman also called in the anonymous tip that got Abel Koontz arrested and took photos of Veronica that were sent to Lianne Mars ("You Think You Know Somebody"). Unfortunately, Amelia DeLongpre didn't stay away long. When Abel tried to get Veronica to find his daughter, Veronica found out that she had called Kane Software from a payphone across the street and confronted Wiedman about it. Later on, when Veronica found her body, Clarence was there and confessed to her that Amelia had asked for more money.
As it turned out, it was Amelia's new boyfriend, Carlos Mercado, who had wanted the money and after he got it, he killed Amelia. Wiedman traced the money to Las Vegas and it was implied that he killed Carlos ("Rat Saw God"). Wiedman made another appearance when Aaron Echolls was acquitted. In Aaron's hotel room, Clarence assassinated him with two bullets. Afterwards, he called Duncan Kane in Australia, who asked "CW?" Wiedman responded, "It's a done deal." ("Not Pictured"). Some have speculated that this was also an allusion to the WB-UPN merger into the CW.