A Los Angeles neighborhood has revived its crime-watch program after police raided a local home and found a sophisticated marijuana grow operation, the Los Angeles Times reported April 20.

The Diamond Bar Neighborhood Watch is once again in business, with neighbors keeping any eye out for suspicious activity that could indicate that other grow operations are hidden behind closed doors. Some clues: homeowners who fail to mow the lawn, put out the garbage, or open their windows.

Police recently raided a dozen grow ops in the San Gabriel Valley, arresting 10 suspected growers and seizing 12,000 marijuana plants.

"We have to go back to knocking on doors and taking flowers to our new neighbors," said Diamond Bar resident Paulette Horton. "From now on, we're going to introduce ourselves to whoever's out in front of an empty house."

"Now I'm driving around thinking, 'Whose shades are closed?'" said Mehrbanoo Ostowari, another resident.

"It seems like [growers are] picking neighborhoods that are fairly nice -- some of them very nice -- where neighbors are friendly but not overly involved," said Lt. Jim Whitten of the Los Angeles County Sheriff's Narcotics Bureau. "People are so busy with their lives coming and going they think they just won't be noticed, and it worked for a while, and it's probably still working in some places."