‘Whodunit’ Is First

April Dion is Hollywood’s idea of a hacker. That is, a blond Sandra Bullock with a Rachel haircut, ripped jeans and a vicious pout.

She admits, peering over the top of her sunglasses, that she doesn’t know anything about computers. Except one thing. Fans like to save her image from a previous on-line ad to their hard drives.

“My agent called and said, ‘Did you hear? All these kids are downloading you,”’ the 22-year-old says, making it sound dirty.

She smiles and saunters to lunch - with any luck the first sex symbol of episodic Internet.

Executive Producer Dean Vallas certainly hopes so, as he films Dion for “Whodunit,” the first on-line TV series.

Vallas and partner William D’Angelo hope to provide an interactive weekly mystery with video, audio and text on the Internet.

While cable companies and media conglomerates such as Time Warner experiment with video on demand, the Los Angeles duo are trying to make the much-promised technology work on the NETwork, a site on the global Internet computer network.