Montgomery County police did nothing wrong in sending mature-looking underage police "Explorers" to a Rockville delicatessan to try to buy beer, a county judge has decided.

Circuit Judge William C. Miller rejected an appeal by the owners of the Twinbrook Delicatessen, who were fined $1,500 last March by the county Board of License Commissioners for selling alcohol to a minor in November and again in January.

The delicatessen owners argued in court papers "that these so-called sweeps" by police were "not in the public interest because of the use of mature-looking minors to decoy the innocent into committing a crime." They owners also maintained that the action was unfair because county-owned liquor outlets are not subject to the same controls and penalties and that using unbudgeted county money to buy alcohol illegally "should be condemned."

Martin Curtis Kilpatrick, 17, one of several dozen youths in the Montgomery County Police Law Enforcement Explorers program, went into the Veirs Mill Road delicatessen last Nov. 13 and bought a quart of beer as two officers watched. On Jan. 22, another 17-year-old Explorer, William Huber, also watched by officers, bought a bottle of beer there.

Kilpatrick was described in court papers as six feet tall and weighing 155 pounds; Huber measured 6-2 and had a moustache.

In deciding the case on Wednesday, Miller wrote that police had not illegally induced the sales clerk into selling beer to a minor because the officers made no effort to disguise the Explorers or make them look older than they were.

The judge agreed that the sales clerk "did not knowingly or intentionally sell beer to these minors" and was not "predisposed to commit crime." But he wrote that the law "seeks to punish those who fail to exercise due caution." While the violations were unintentional, he wrote, the store owners "may have shown a want of due care."

The "bottom-line purpose" of sending the Explorers into beer and wine stores "is to reduce the sales and consumption of alcoholic beverages to minors," Miller wrote'.