Tragedy struck in the area near Murrieta, California early on Saturday morning when a twin-engine plane crashed, killing all six people who were on board, as CBS News reports.

The accident occurred as the plane was attempting to land at the French Valley Airport, and poor visibility was said to be the cause.

Ill-fated flight

According to the outlet, the flight's journey began at roughly 3:15 a.m. At Las Vegas' Harry Reid International Airport, and the crash occurred about an hour later.

Once it was approximately 500 feet from the runway in Murrieta, the aircraft was said to have come “down in a field,” at which point it became “fully involved in fire,” according to the Riverside County Fire Department.

The resulting conflagration was fairly significant, burning roughly an acre of surrounding vegetation before it was successfully contained.

Sadly, all of the six souls on board were declared dead at the site, and all of those who perished were reportedly adults.

Marine layer blamed

Investigator Elliot Simpson of the National Transportation Safety Board (NTSB) offered some insight as to what precipitated the unfortunate events, as ABC 7 in Los Angeles noted.

The official explained that a marine layer of dense fog descended on the immediate area before the plane's scheduled landing, making it difficult for the pilot to bring the flight to its expected conclusion due to the ensuing visibility problems. “The pilot reported to air traffic control that he was going to perform a missed approach, which generally happens when the pilot can't see the runway,” Simpson said.

The pilot was then cleared by air traffic control to attempt the maneuver, then clearing him to land after the initial approach, but the plane crashed before reaching the runway.

Treacherous flying conditions were confirmed by witnesses who were in the area on the day of the crash, with Moon Valley Nurseries employee Patrick O'Neil stating, “It was very foggy this morning. It was almost like you were in a snowstorm where you can't see a couple feet ahead of you. So, just getting to work was very challenging. So, I can only imagine trying to land any type of plane, you know, here at the French Valley Airport.”

Investigation underway

An on-site investigation has been launched by the NTSB and is likely last up to two days, with the Federal Aviation Administration and officials from Cessna – the manufacturer of the aircraft – taking part, according to ABC 7.

It is expected that preliminary findings will be available in about two weeks, with a complete report to follow in roughly 18 months.

As CBS News noted, this is the second deadly plane accident to befall the area within a week, with yet another Cessna craft having crashed near the same airport on Tuesday afternoon.

That incident, in which an airplane made contact with a building, left one dead and three others injured.