The NTSB is charged with finding out the probable cause for why UPS Flight 2976 crashed in Louisville. Here's what to know about the investigation.

The crash near the Louisville Muhammad Ali International Airport marked the deadliest accident in UPS Airlines history.

LOUISVILLE — The death toll has risen from the deadly UPS plane crash at Louisville Muhammad Ali Airport. Mayor Craig Greenberg said that a 13th person has died as a result of the crash. The victim was at an area hospital, where they died on Nov. 6, the mayor said during a vigil, The Louisville Courier Journal reported.

The death toll climbed to at least 13 on Wednesday, Nov. 5, and several people remained unaccounted for, said Louisville Mayor Craig Greenberg.

At least 12 people were killed and several others injured after a UPS plane crashed shortly after taking off from the Louisville International Airport on Tuesday.

The UPS plane was departing for Honolulu from the Louisville Muhammad Ali International Airport when it crashed at about 5:15 p.m. local time Tuesday, authorities said. Video of the crash showed flames on one of the plane's wings,

The crash of a UPS plane in Louisville, Ky., has disrupted the shipper's air cargo headquarters, delaying some deliveries.

The Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB) will lead the investigation into the incident.