It’s something that no one ever wants to think about: losing your life while on vacation and engaging in a fun activity. But that is apparently what happened to four people when a tour helicopter from Las Vegas crashed on a mountainside between Lake Mead and Henderson earlier this week.

On Wednesday around 4:30pm or 5pm, the Eurocopter AS350 owned by Las Vegas-based Sundance Helicopters went down in a steep canyon in the River Mountains as is was flying toward Lake Mead and the Hoover Dam. Two of the passengers have not yet been identified. But the other pair was a married couple from Utica, Kansas who were reportedly celebrating their 25th wedding anniversary in Las Vegas. There is no word on whether the pilot, who was also killed, had communicated any problems about the aircraft to people on the ground prior to the crash.

Investigators with the National Transportation Safety Board are at the crash site trying to gather evidence into what may have caused this tragedy. The NTSB says that a preliminary report about the incident may be issued later in December, but that the final findings won’t be released for several months.

It’s the second deadly tour chopper crash for Sundance Helicopters in a little over eight years. Back in September of 2003, a pilot and six passengers died when one of the company’s helicopters went down at the Grand Canyon West Airport.

But whatever the NTSB reports say, it appears that Sundance Helicopters will probably be held responsible for the deaths of the four helicopter passengers. As a result, the company will likely be named as a defendant in wrongful death lawsuits filed by the heirs of the victims.