The man, John Ng of Sunnyvale, is scheduled for an April 25 hearing, when a judge will determine if the case can proceed to a formal trial.

According to Santa Clara County Deputy District Attorney Matt Braker, however, the only way Ng will not go to a formal trial is if he pleads guilty to the charges that have been filed against him. Ng on Feb. 11 entered a plea of not guilty.

The charges are possession of a tool for an unlawful purpose, attempted burglary and attempted rape. "It's a very serious case, and he poses a significant threat," Braker said.

In December, sheriff's deputies caught Ng in the act of prying open the back door of a Cox Avenue home. They found on Ng and in his car items and handwritten instructions on note cards that led them to believe that he planned on breaking into the house and raping the resident.

The 52-year-old suspect had been a friend of the woman for seven years.

Braker is preparing the case for the preliminary trial and continuing with his investigation. There could be additional charges for Ng, and Braker said he could not comment on whether Ng may face charges related to other cases.

The Saratoga woman and sheriff's officers are expected to testify at the preliminary trial.