The names of 321 fallen officers were added to the National Law Enforcement Officers Memorial last night at the annual Candlelight Vigil in Washington, D.C.

An estimated 20,000 people attended the 25th annual vigil, which honored 120 officers killed in the line of duty last year and another 201 fallen officers dating back to 1814. Customs Inspector John Stout was killed in the line of duty nearly 200 years ago while attempting to arrest notorious pirate Jean Lafitte during a slave auction.

"Whether an officer is killed one year ago or two centuries ago, he or she will always be remembered and honored at the National Law Enforcement Memorial," said Craig Floyd, chairman and CEO of the  National Law Enforcement Officers Memorial Fund .

Last year's total of 120 officers killed in the line of duty was a significant reduction from the 169 killed in 2011 and the lowest number since 1959. All of the speakers at this year's vigil praised this trend as a move in the right direction and focused on the need to further reduce line-of-duty deaths.

U.S. Attorney General Eric Holder led the candle-lighting ceremony and delivered the keynote. "Although no words and no ceremony can erase the pain we feel at each tragic and untimely loss, my hope is that the families, friends, and colleagues of these fallen heroes can find peace in the certain knowledge that they died doing what they loved. They helped to make this world a far better and safer place," Holder told the crowd.

Also speaking at the vigil was Department of Homeland Security Secretary Janet Napolitano. "We come together among these silent stone walls, to pay our respects to these officers and to always remember their lives, their contributions, and the examples they set," she said.

One particularly poignant moment during the vigil was the speech by Madeline Neumann, president of the Concerns of Police Survivors (COPS) . Neumann told how she became a "survivor" in 1989 at the age of 22 when her husband, Keith Neumann was killed in the line of duty. She told the family members of the fallen officers that they didn't choose to be "survivors" but they can choose to "survive."

The vigil, the centerpiece of National Police Week , concluded with the candle lighting ceremony. Thousands of officers and civilians in attendance held the candles high as a blue laser light pierced the sky above them, serving as a stark reminder of the thin blue line.

Special guests during the ceremony included representatives of the Boston-area agencies that investigated the Boston Marathon bombing and eliminated the threat. These special attendees included Director Robert Mueller of the FBI, Col. Timothy Alben of the Massachusetts State Police, Superintendent Willie Gross of the Boston Police Department, and Chief Ed Deveau of the Watertown Police Department.

The 25th annual Candlelight Vigil was presented by National Law Enforcement Officers Memorial Fund and Target Corp. To learn more about the names added to the wall this year, click here .

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