Suffolk County police have launched a program urging residents to lock their car doors to discourage thefts.

The “Lock It!” campaign was announced Tuesday by Police Commissioner Timothy Sini and Nick Amarr, president of Suffolk County Crime Stoppers.

The campaign includes public service announcements on radio and television through September, and officials said many malls and shopping centers plan to display “Lock It!” posters in an effort to drive down crime.

“We’re raising awareness,” Sini said Tuesday. “We don’t want people to be victimized in Suffolk County.”

Sini said that while the number of reported larcenies are down — 2015, in fact, had the lowest number in 10 years — crime-mapping programs have shown outbreaks often occur in clusters, typically a mall parking lot or a block.

Such vehicle break-ins can be “crimes of opportunity,” undertaken by “people acting out of desperation” and, as such, often the perpetrators are petty criminals or people who have drug addiction, he said.

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In these cases, a perpetrator might target a block or a parking lot and simply try vehicle door handles.

If the door is unlocked, Sini said, a suspect will rifle through the vehicle to steal loose change or other valuables. But, he said, if the door is locked, often such perpetrators will move on to the next vehicle — instead of breaking a window to gain entry.