The suspect, who is believed to be a male in his 30s, approximately 6 feet tall and 160 pounds, was seen walking casually out of a residential backyard on Via Tesoro Court off Chester Avenue after the home's alarm system went off.

Police were able to retrieve a videotape of the suspect in action, which showed the male dressed in dark clothes and wearing a beanie.

A couple of days later, a similar incident occurred on Oak Street.

According to Santa Clara County Sheriff's Deputy Ken Nelson, the suspect knows exactly what he is doing and what he wants. He is extremely skilled and knowledgeable in fine and expensive gems, and has stolen more than a half-million dollars' worth of jewelry within the last two months.

"The suspect is very selective. He can tell instantly whether a stone is real or synthetic," Nelson said.

Det. John Spagnola, who has studied this case since the beginning, said that the suspect "has this business down to a science."

"The individual knows where to go in the house," said Spagnola, which means that he has carefully scoped out the area and possibly knocked on the door as a solicitor. "The master bedroom and bathroom are the most common places where people leave their jewelry."

He added that the suspect has everything mapped out before executing his plan, from the escape route to the amount of time it takes for a resident to search the house should an alarm go off.

According to Spagnola and Nelson, houses with backyards leading to trails, open fields and highways are favorable targets for burglars like the jewel thief because it gives the suspect a chance to get away faster with less of a chance of being seen, as opposed to houses with backyards that face one another.

Despite leads, police have not been able to link any individual to the jewel burglaries, partially because the suspect appears to go back and forth between the Saratoga and Los Gatos area to avoid any consistencies in one area. He is believed to be moving north toward the wealthier areas in Palo Alto.

Also, "professional burglary cases like these are done by people who are slick and sophisticated," Nelson said.

Many of these people operate in groups of two to four and go door to door, pretending to sell goods or claim they are with a legitimate organization. Nelson said that this jewel thief may be working with a female accomplice.

In efforts to protect residents and their homes, Nelson has been helping owners set up a Neighborhood Watch system. He said the one on Via Tesoro has full participation from the residents.

He strongly urges residents to familiarize themselves with their neighbors and the area, as well as the policy regarding solicitor permits. According to a Saratoga ordinance, all solicitors must carry photo identification and a permit, which costs about $100. Nelson strongly suggested that all residents who encounter a solicitor who does not have photo identification call the police with a description of the individual.

George Thomas, who is in charge of the Neighborhood Watch in the Sunland Park area off Quito Road, said his neighborhood has not gotten as many solicitors as other areas because of the strong network among the residents.

"We try to look out for one another," said Thomas.

Like Nelson, Thomas urged residents to be observant and to keep an eye out for any suspicious activities or cars that don't belong in the area.

"Start a chain reaction within the neighborhood," Nelson said. "The more witnesses there are, the more information police will have to catch the individual and the safer the residents will be."