New Yorkers were shocked this past Thursday when a helicopter suddenly plummeted into the Hudson River, killing all six people on board.

While an investigation of the tragedy is being carried out by federal authorities, one piece of evidence is missing. 

Helicopter lacked a flight recording device

According to The U.S. Sun, officials with the National Transport Safety Board (NTSB) revealed on Saturday evening that the aircraft lacked a flight recording device.

What's more, the Sun also reported that the Bell 206 L-4, which was owned by tour company New York Helicopters, also appears not to have been equipped with video or camera recorders.

NTSB explained that the helicopter had last undergone a thorough inspection on March 1 and had successfully conducted seven previous tours before it came apart in midair.

The accident's death toll consisted of helicopter pilot Sean Johnson as well as passengers Agustin Escobar, his wife Mercè Camprubí Montal, and their three children.

Brother of victim: "We will keep your smile alive every day of our lives"

An executive with the European technology conglomerate Siemens, Escobar booked the helicopter tour to celebrate the birth of one of his children.

Joan Camprubí Montal is the brother of Mercè Camprubí, and he spoke to reporters at a press conference about the loss of family members.

"We will never forget you. We will keep your smile alive every day of our lives, and I believe that's the best legacy we can give you," Montal said in Spanish.

"This is a really difficult situation, but we are overwhelmed by the massive condolences we've received. They left together. They left without suffering, and they left with a smile on their faces, and that is important for us," he continued.

"As a family we want to honor their happiness and their smile forever. We want to move the bodies, as soon as possible, back home with all the family to rest in peace together," Montal stressed.

New York mayor: "We are here with you"

New York City Mayor Eric Adams spoke up as well, saying, "We mourn the lives of Agustín, Mercè and their three beautiful children, Victor, Mercedes and Augustine. Are hearts our broken."

"You have 8.5 million New Yorkers who want to say to the family members and to the wider Spanish community that we are here with you," the mayor pointed out.

"And this symbolic gesture is our way of knowing and acknowledging that our words cannot bring back their family members, but it is our way of saying as New Yorkers, we stand united with this family during this moment of grief, and their grief is our grief," Adams added.