(Reuters) - The massacre on Friday of 12 people at a Virginia Beach, Virginia, municipal building was the work a veteran employee who had sent in his resignation hours before opening fire, according to police.

Police tape frames a sign at one of the entrances to the municipal government complex where a shooting incident occurred in Virginia Beach, Virginia, U.S. June 1, 2019. REUTERS/Jonathan Drake

The attack stands as the second-deadliest U.S. workplace shooting since 2000. Here are some of the others:

2015 - 14 dead, 22 wounded

SAN BERNARDINO, Calif. - Syed Rizwan Farook and his wife, Tashfeen Malik, massacred 14 people and wounded 22 others at an office party of his colleagues at the Inland Regional Center for San Bernardino County health workers in 2015. Authorities said the U.S.-born son of Pakistani immigrants and the Pakistani native were inspired by Islamist militants. The married couple died in a shootout with police.

2019 - 12 dead, 4 wounded

VIRGINIA BEACH, Va. - Just before his co-workers had clocked out for the weekend, DeWayne Craddock opened fire at a municipal building on Friday, killing 12 people and wounding four others. The city engineer, who had earlier in the day emailed to declare his intention to quit, was fatally wounded in a gun battle with police. [nL2N23A03T]

2010 - 8 dead

MANCHESTER, Conn. - Minutes after he was fired for stealing beer and empty kegs, Omar Thornton, a driver at Hartford Distributors shot eight people and then killed himself in 2010. Thornton, who was black, in a 911 call blamed the gun violence on racism in his workplace. A police probe later concluded there was no proof of systemic racism at the business.

2006 - 7 dead

GOLETA, Calif. - In one of the few workplace attacks by a woman, former postal worker Jennifer Sanmarco unleashed a hail of bullets at a U.S. Postal Service processing center in 2006. Sanmarco shot dead a neighbor and six postal workers before killing herself.

2000 - 7 dead

WAKEFIELD, Mass. - Edgewater Technology employee Michael McDermott was furious that federal tax authorities were collecting back taxes from his paycheck and massacred seven of his co-workers. The gunman, convicted of the murders, is serving seven consecutive life terms in prison.

2012 - 6 dead

MINNEAPOLIS - After he was fired by a sign manufacturer, Andrew Engeldinger returned to Accent Signage Systems Inc and shot dead five of his former co-workers and a UPS deliveryman. He then turned the gun on himself and ended his life.