Man walks into a Starbucks, says he wants to apply for a job. He’s given an application and a complimentary cup of coffee. Minutes later, he walks around the counter and threatens a barista with a ballpoint pen. He flees with $204 from the cash register and keys to another barista’s 1993 Nissan Maxima, leaving behind the partially consumed cup of coffee.

Dominic J. Wilson is scheduled to stand trial today in the Starbucks case.

“Saliva,” said Ray Wickenheiser, director of Montgomery’s crime lab, “is a good source of DNA.”

DNA testing in the county is expanding from killings and rapes to less violent robberies, burglaries and drug deals. Prosecutors say this will lead to quicker convictions because defendants will cave and plead guilty. Defense lawyers worry that as more DNA samples are pushed through the county’s crime lab, it will boost the odds of false matches.

“It runs the risk of turning the gold standard of evidence into fool’s gold,” said Stephen Mercer, a Montgomery lawyer who has taken on so many of these cases lately that one of this clients calls him “the DNA Dude.”

To read how detectives describe the Starbucks case in their arrest documents, the case appears to reside in the gold-standard realm. The incident took place in 2002, so long ago that the Starbucks in question, along Washington Street in downtown Rockville, doesn’t exist anymore, although there is a new one around the corner.

For years, detectives didn’t make an arrest. They did have a seized coffee cup, though, from which they lifted a DNA sample, according to charging documents filed in Montgomery Circuit Court. In 2007, the details of that sample were entered into a statewide database of convicted felons.

Up popped a connection to Wilson, who shortly after the alleged Starbucks job was arrested on assault and battery charges, according to court records. In March, a Montgomery grand jury indicted Wilson on one count of theft, two counts of robbery and one count of “robbery with a dangerous weapon,” according to a copy of the indictment.

Montgomery’s crime lab has been dogged by backlogs of several hundred DNA cases. It is generally hard to keep labs fully staffed, in part because analysts are in such demand. Wickenheiser, the lab director who took over in March, said additional employees have cut the backlog to about 100 cases. His staff is running validation tests on new countertop robots that can do such things as automatically extract DNA from other cellular components. Wickenheiser hopes the robots will start producing evidence for cases by the spring. Coupled with a new gene-sequencing machine, the robots could increase DNA analysis output by at least 30 percent, he said

Wickenheiser said he wants to make DNA testing routine for all robberies and residential burglaries in Montgomery within five years. Already, courthouse attorneys are dealing with more DNA cases.

“In the early days, you would see them in rapes and murders,” said Paul DeWolfe, the chief public defender in Montgomery, who says DNA evidence now shows up in virtually every type of crime.

As that happens, evidence technicians are swabbing for DNA on such things as gun handles, car interiors, cocaine bags and articles of clothing used in strangulation attempts. The problem, said Mercer, is that although the evidence can show that a suspect was near the evidence, it doesn’t necessarily show that the suspect committed a crime.

An article of clothing used in a strangulation could have been touched by the suspect weeks earlier in innocent fashion, he said. Also, surface samples often require DNA lab analysts to sort out the suspect’s DNA from other people’s, introducing a greater chance of error.

Wickenheiser said he has established a “prioritization policy” with detectives and prosecutors that is expediting the most urgent cases. He said detectives and prosecutors know to seek other evidence tying suspects to crimes. And he said that as DNA testing gets more exacting, it simply makes sense to use it more. His analysts now can pull evidence out of DNA samples weighing 100 picograms, a picogram being one-trillionth of a gram. Such precision, he said, can also exonerate innocent suspects.

One of Montgomery’s top prosecutors, Laura Chase, a deputy state’s attorney, said defense lawyers have feared challenging DNA evidence before a jury. As DNA evidence moves to less-violent crimes, she said, “I think it will encourage pleas. It always has encouraged pleas, and that will make the system more efficient.”