In a letter to law enforcement officials, gubernatorial candidate Steve Poizner today charged that Mike Murphy, a key consultant to Meg Whitman's campaign, threatened to drive him out of the GOP primary.

Poizner, the state's insurance commissioner, contended that Murphy crossed an ethical line by threatening to "tear me up" by spending "$40 million plus."

The alleged threat was sent by Murphy on Wednesday in an e-mail, Poizner said at a Sacramento news conference this morning. He also claimed Whitman's staffers have been calling his own staff in an attempt to pressure him to step aside.

"They're trying to cancel the election effectively," Poizner said.

The e-mail from Murphy included a suggestion that the Republican Party unite behind Whitman and support a Poizner bid for U.S. Senate in 2012, which Murphy said "could be a strong GOP year." Murphy noted that U.S. Senator Dianne Feinstein, a Democrat, would be "78 or 79 years old" by then.

Poizner passed out copies of Murphy's e-mail to reporters, who were told it has also been turned over to the FBI, state attorney general's office, U.S. attorney's office, California Secretary of State's Office and the state Fair Political Practices Commission.

In a bizarre wrinkle, California Attorney General Jerry Brown is the presumed Democratic candidate in this fall's election.

Whitman, a former CEO of eBay, has thus far contributed $39 million to her campaign. Poizner, a former Silicon Valley entrepreneur, has contributed $19.2 million of his own money.

Whitman campaign officials could not immediately be reached for comment.