I was there... in Aurora, Denver, during the Batman mass cinema shooting

When film fan Casey Sioorio decided to check out the new Batman film at her local cinema in Denver, she thought it would just be another fun night.

Little did she know that for those at the Century Theater in Aurora on July 20, a routine cinema trip would turn into one of the most horrifying mass murders in American history.

Casey planned to see the midnight showing of The Dark Knight Rises on that fateful night, but a last-minute decision saved her from the carnage which saw 12 people shot dead and dozens more injured.

Casey was minutes from entering the cinema before a potentially life-saving change of heart saw her change her plans.

She had planned to watch the film at midnight, before starting her overnight shift at a local bakery shortly after.

After deciding against seeing the film at the last minute, the 26-year-old headed to her night shift in the early hours, where she soon realised she had dodged disaster.

Within hours of starting work she learned of the mass shooting just around the corner, where gunman James Holmes burst into a screening and gunned down a dozen cinemagoers.

Holmes entered the screening through an emergency exit wearing a gas mask, with victims initially thinking it was a stunt to do with the film.

He moved up the stairs, throwing tear gas into the audience and shooting at random, as petrified film fans fled for their lives.

The final tally of 12 dead and 58 injured made Aurora, at the time, the worst mass shooting in the U.S. since Columbine.

It was all the more tragic for Casey once she learned more about those involved.

Among those targeted in Aurora was her distant cousin Ryan Lumba, who was critically injured after being hit in the stomach by a shotgun blast.

College hopeful Ryan, 17, made a remarkable recovery, but his scarring ordeal is a constant to reminder to Casey that she very narrowly avoided being in the same screening herself.

Recalling the moment she heard about the tragedy, Casey told Yahoo! News: "While I was at work I could hear people talking in hushed tones and someone mentioned a shooting - but noone would tell me what was going on.

"Eventually a colleague came up to me and said nervously, 'There's been a shooting at the theatre'.

"Throughout the shift my phone was ringing constantly with people asking where I was.

"I told them I was fine, but it was only when I got off my shift and found out the full details at home I got the most horrific news.

"As soon as I found out about my cousin I lost it and freaked out - it was one of my youngest cousins that was in the theater."

Casey's heart pounded as the true horror of the tragedy unfolded - her first thought was that the gunman might continue his shooting spree elsewhere in Aurora.

She added: "I couldn't help but feel scared straight away. I stayed where I was told, but my mind started to race.

"I wondered, 'What's going to do next? What if he comes around here and carries on shooting?"

In the immediate aftermath of the shooting, Casey said, like many, she struggled to come to terms with why someone would want to take so many innocent lives.

"At the time, I just remember thinking, 'What is the purpose of this, what does he want to do?'", she added.

"I started to hate this individual becuause I couldn't stand the fact that he hurt and killed so many people."

Casey said that although the Century Theater in her hometown of Aurora has remained closed ever since the shooting, she hopes it will reopen in one form or another in the future.

She said: "There has been talk about the theatre being remodeled and opened again, but I'm not sure how to feel about that.

"From a convenience point of view there should be somewhere where people can see new films, but they would have to give the place a complete overhaul."