The entire nation finds itself in mourning today following a deadly attack in Las Vegas. Reports are, as of this writing, that at least 50 people are dead and as many as 400 wounded as a man with a gun opened fire on people attending an open-air country music concert festival in the city.

A gunman at a Las Vegas hotel rained a rapid-fire barrage on a huge outdoor concert festival on Sunday night, sending thousands of people fleeing. At least 50 victims died, and hundreds of others were wounded, officials said, making it one of the deadliest mass shootings in United States history.

“We believe the individual killed himself,” said Sheriff Joseph Lombardo of the Las Vegas Metropolitan Police Department on CNN.

Online video of the attack outside the Mandalay Bay Resort and Casino showed the singer Jason Aldean performing outside at the Route 91 Harvest Festival, a three-day country music event, interrupted by the sound of automatic gunfire. The music stopped, and concertgoers ducked for cover. “Get down,” one shouted. “Stay down,” screamed another.

Several SWAT teams were sent to the hotel immediately after the first reports of the shooting at 10:08 p.m., and officers overheard on police radio reported being pinned down by gunfire. Shortly before midnight the Las Vegas police reported that “one suspect is down,” and soon thereafter the police said they did not believe there were any more active gunmen.

Police identified the shooter as a 64-year-old resident of Mesquite, Nevada.

A video posted on Twitter captured the early moments of the attack.

The gunfire sounds like a fully-automatic weapon, the kind that is covered by the National Firearms Act and is tightly controlled. At this time, there’s little information about the weapon or the man who used to take so many innocent lives.

Also lacking at this moment is any information on the killer’s motivation. His brother told The Daily Mail that his brother was apparently just someone who “snapped.”

He said: ‘He was just a guy. Something happened, he snapped or something’.

He’s my brother, we don’t have a very close relationship but we talk occasionally. There’s no rhyme or reason here, it makes no sense’.

He said: ‘She has nothing to do with this, at least from my perspective.

‘He was just a guy. Something happened, he snapped or something, he was just a guy.

‘He has no political affiliation, no religious affiliation, as far as we know. This wasn’t a terror attack’.

All of this adds to the mystery of just what happened to make a man so determined to mow down innocent concertgoers who were simply out for a good time in a city long associated with good times.

EMTs treat the wounded following deadly shooting in Las Vegas (photo from AP)Also killed was an off-duty police officer. Two on-duty officers were among the wounded.

One local off-duty officer died, while two others who were on duty were wounded by gunfire, said Clark County Sheriff Joe Lombardo. Of the two wounded, one is stable after surgery and the other sustained minor injuries, he said.

Our thoughts and prayers are with all who were affected by this senseless tragedy.