A family is in mourning after their 10-month-old puppy was found dead following a flight from Houston to New York City.

On Monday, the french bulldog, named Kokito, was on board a United Airlines flight and was originally placed in TSA-compliant pet carrier that was designed to be small enough to fit underneath any of the seats.

However, a flight attendant allegedly forced the family - which included a mother and her two children - to place the animal and its carrier in an overhead bin for the entire four hour flight, as it was partly obstructing the aisle.

Those on the airplane reportedly heard Kokito bark throughout the flight, but were unaware it had passed away until they landed at LaGuardia Airport.

Passenger Maggie Gremminger, 30, said she wasn't the only one horrified over the incident, as the flight attendant became "frazzled" and became insistent she was unaware there was actually a dog in the carrier.

Following the incident, Gremminger posted on Twitter to express her grief: "I want to help this woman and her daughter. They lost their dog because of an @united flight attendant. My heart is broken."

She said when the woman found her dog had passed away, she sat on floor of the airplane aisle, sobbing.

"Many other crew members were contacting additional help and offering a blanket to the young girl who seemed cold. They were confused at how that individual flight attendant could have done this, but did not seem to take any sides or blindly defend," Gremminger said. "They were professional and did a wonderful job gathering information and being as supportive to the mourning family as possible."

According to United spokesperson, Maggie Schmerin, the airline has taken full responsibility for the incident.

"This was a tragic accident that should never have occurred, as pets should never be placed in the overhead bin. We assume full responsibility for this tragedy and express our deepest condolences to the family and are committed to supporting them. We are thoroughly investigating what occurred to prevent this from ever happening again," the statement read.

Gremminger said the flight attendant should also be held accountable for her role in the Kokito's death.

"My only thought is that if it had been me, it would have been a hard scenario. The flight attendant is the authority figure, who should be trusted. I was thinking "˜maybe there is an improved ventilation system' or something of the sorts," Gremminger said, sadly acknowledging she was wrong.

Do you think the flight attendant should lose her job for the role she played in the tragic accident?

[H/T: FOX News, Global News, PEOPLE]