For decades, a bronze plaque commemorating 15 Petaluma servicemen killed in Vietnam sat as a quiet reminder of the toll of war on a small town thousands of miles away from the battle zone.

But in a few frantic moments, likely under cover of darkness, a thief made off with the plaque from its pedestal in Walnut Park.

Petaluma veterans are shocked and wounded by the act, which they say feels like a betrayal, a very personal attack — ostensibly for the scrap metal value.

"That's getting pretty low to steal a war memorial," said Steve Kemmerle, who was an Army MP from 1969 to 1971 and organizes the Veterans Day Parade in Petaluma each year.

"I'm just dumbfounded," said Joe Noriel, president of the Petaluma Museum, which held a successful Vietnam Experience exhibit in 2010 that brought together veterans and members of the Vietnamese community.

It's an act that is becoming more common, with metal thefts from war memorials being reported in just the last four months in Los Angeles, Connecticut, England and Wales. On Monday, a British newspaper reported the recent theft of a plaque marking the 500th anniversary of the Battle of Flodden between England and Scotland.

The Vietnam memorial plaque, about 25 inches by 30 inches and an inch thick, was cut from its stone base on a stand near the gazebo at Walnut Park off Petaluma Boulevard South and D Street.

Noriel and veterans became aware of the theft this week, but police Lt. Tim Lyons said a transient who frequents the park said he noticed it missing during the week before Christmas.

"We have no leads," he said, "but it was probably for the metal value."

Similar thefts have increased markedly over the past several years as prices for scrap metal have increased with demand in China and elsewhere overseas. Per pound prices of copper a few years ago hovered at $1.30 in 2009 to a high of about $4.50 a pound in 2011, according to infomine.com, which tracks metal prices.

In Petaluma, thieves have stuck the PG&E yard more than once, stealing copper wire and tools. Thieves have hit light posts and even railroad crossing arm control boxes, stripping them of the recyclable metals and leaving the devices malfunctioning.

Lyons said it would be difficult for anyone to sell the Vietnam war plaque. Police are alerting scrap metal recyclers to be on the lookout for it.

"The recyclers know, unless they're doing illegal things themselves, that if they see something like this come in, they're supposed to call police," he said. "You wonder where they could take it or would they try to melt it down first?"

The thieves must be heartless, Kemmerle said.

"That's sort of like sacred ground, to steal a memorial," he said. "For the scrap value of it, I don't know, maybe 100 bucks?"

The irony, Noriel said, is that the plaque was installed in the mid-seventies and survived the turmoil and emotion of the day that swirled around the war in Vietnam.

"It withstood the volatile emotions of a divided country after the war, but ultimately lost the battle due to the economy," he said.

Thieves seeking a quick profit on metals have hit other memorials around the world. In October in Los Angeles, a large bronze plaque was stolen from the Mexican American All Wars Memorial built in 1947. Five bronze World War I plaques were stolen in New Britain, Conn., in October. In Great Britain, 103 small plaques with the names of dead WWI soldiers were stolen from a Welsh church in November.

While Petaluma veterans are holding out some hope for the safe return of the plaque, they also are mobilizing a fund-raising campaign to replace it and better secure a new memorial. Estimates are at least $1,000 will be needed to replace the plaque.

The committee will meet next week to discuss possibilities. Tax-deductible donations may be sent to the Petaluma Museum at 20 4th St., 94952. For more information on the design process, call 778-4398.

Police are asking anyone with information about the theft or the plaque to call Officer Bill Baseman at 707-778-4372.