A duck boat involved in last week’s fatal crash that killed five people and injured dozens did not have an axle repair that was recommended in 2013, the National Transportation Safety Board (NTSB) said Sunday, according to the Associated Press (AP). The deadly incident occurred Thursday when an amphibious duck boat and a motorcoach collided.

Ride the Ducks International, which rebuilt the boat in 2005, issued a warning two years ago about potential axle failure and recommended a specific repair or increased monitoring, NTSB member Earl Weener reportedly said at a news conference.

"This particular duck had not had the fix," Weener said, according to the AP, adding that it was unclear if the company that owns the vehicle -- Ride the Ducks of Seattle -- was aware of the warning. The NTSB also did not reveal what prompted the warning or how the potential failure was discovered.

In a briefing Saturday, Weener described an axle as having "sheared off -- for what reason yet we don't know."

On Sunday, a spokeswoman for Harborview Medical Center reportedly said that the fifth victim -- identified as a 20-year-old woman -- died at the hospital, while four other students of North Seattle College died at the scene of the crash.

North Seattle College said in a statement that about 45 students and employees from its international programs were on the charter bus. At least 13 people were at Seattle hospitals Sunday for treatment, authorities reportedly said.

Ride the Ducks of Seattle owner Brian Tracey said Sunday night that operations of its duck boats will remain suspended until all the vehicles are inspected, the AP reported. The inspection will reportedly be conducted by the state Utilities and Transportation Commission.