Hoping for a big celebration before entering her third decade, Instagram influencer Yekaterina Didenko hosted a big party with her friends for her 29th birthday.

But it all went horribly wrong when three of her guests died and four more were injured due to a major decorating oversight that's now up for investigation.

Didenko was keeping track of the big event via her Instagram stories, which have expired since the tragedy. The day of the party, the first few entries were fun and optimistic, depicting a party with lots of food and drinks to go around, sexy swimsuits, and pole-dancing games.

But little did anyone know what would happen next, when Didenko appeared crying in her next Instagram story, claiming she didn't know what had happened.

Her husband, Valentin Didenko, had filled their pool with more than 50 pounds of dry ice, which is loaded with carbon dioxide, to create a stunning visual background for the party.

But when Didenko's husband jumped into the water, unaware of the consequences, he soon went unconscious and was pronounced dead at the scene.

Didenko said:

"I thought it was not true. It was a nightmare."

Two others were also pronounced dead at the scene from exposure to dry ice, identified as Natalia Monakova and Yuri Alferov, both 25 years old.

Four others were sent to the hospital with significant injuries, including poisoning and chemical burns.

An investigation into the tragedy has since been opened by the Russian Investigative Committee to confirm the nature of using a dangerous product at the party.

Though dry ice is fairly commonly used for haunted houses and nightclubs and other similarly stunning nightlife events, there are precautions that have to be in place, including the coverage of water and ensuring the area in which the ice is being used is properly ventilated.

Whether or not the Russian Investigative Committee thinks so, there are some suspicions floating around online, given that Didenko, who is a pharmacist, was unaware of the precautions associated with dry ice, despite its primary ingredient.

No matter what comes of the investigation, what happened at the birthday party was a tragedy.

Hopefully more people who are interested in using dry ice will do their research first and make sure they're taking all the appropriate precautions to keep everyone safe.