13 people have been killed in the Washington shooting. The killer is a veteran

Washington mayor Vincent Gray said Monday that the number of people killed in the shooting at the U.S Navy's Marine Systems Command has risen to 13, including the gunman and Navy veteran Aaron Alexis The shooting happened at 8:20 a.m local time, which is the bloodiest incident in Washington since the "September 11" incident in 2011, and the event that has caused the largest number of deaths in Washington since 2001 In 2009, there were two subway collisions in Washington, killing nine people In 2009, a white supremacist shot and killed a security guard at the Holocaust Memorial in the United States Today's shooting death toll is far higher than the record for emergencies in the past few years To respect and mourn the victims of the shooting, President Barack Obama has asked the White House, federal government agencies and all military agencies stationed abroad to lower the flag by half until Friday The United States Congress has also lowered the flag by half At present, part of the information about the killers has surfaced According to the US Navy, Aaron Alexis is a 34 year old Navy veteran living in Fort Worth, Texas He served in the US Navy for nearly four years and retired in 2011 Before joining the army, Alexis was arrested by Seattle police for shooting at a vehicle's tires in 2004, police in Seattle, Washington, said Alexis's father told Seattle police his son had PTSD and could not control his anger At the time of September 11, 2001, he was actively involved in the rescue work But today, Alexis, armed with assault rifles and pistols, strafed the crowd and was killed in a firefight with Washington police At present, no one can explain what happened to Alexis, leading him to point his gun at the command of the marine system Navy officials said they were still investigating whether Alexis had been hired as a defense contractor or as a marine systems command Police in Washington have revealed that the identification card of former Marine Sergeant Ronnie chase was found near Alexis's body They are investigating whether Alexis successfully used the card to enter the headquarters building In an effort to catch the killer as soon as possible, FBI official Valerie Paraff called on those who knew anything about Alexis to contact the FBI immediately to help solve the case Lanier, the head of police in Washington, said it was unclear what the gunman's motive was In addition to Alexis, a black gunman was still at large, wearing an olive green military jacket and possibly a long gun Remind surrounding residents and office workers to "avoid on the spot" and not go out Although the cause of the shooting is unclear, Vincent gray noted that there is no information at this time that there is a link between the shooting and terrorist activities, although "this possibility cannot be completely ruled out" The shooting has had a huge impact on Washington The Senate, which is only six minutes from the low point of the incident, suspended the meeting until the morning of the 17th, and imposed a comprehensive blockade for investigators to search The highly watched local baseball game was announced a day later U.S President Barack Obama condemned the shooting of the U.S Navy headquarters as a "cowardly act" and vowed to launch a comprehensive investigation and bring the murderer to justice While condemning the violence, more people choose to show their support for the victims of the shooting through their own actions A company in the United States announced the same day that it would send the staff of the marine system command home free of charge A candlelight vigil will be held in central Washington tonight to express people's mourning for the dead and pray for their early recovery.