The corpse was found in waters close to the falls three days ago. Al Adawi's family received the tragic news after authorities cross-checked his dental and fingerprint records.
"It has been officially announced that the recovered body was that of Qassim," the man's brother-in-law said, according to Gulf News.
He was reported missing in New York City, U.S., but the heavy flow of the water transported his body to the Canadian side of the falls. Niagara Falls consist of three distinctive waterfalls and are considered an international border between Canada and the U.S.
Following news of his passing, the kingdom's ambassador to the U.S. Princess Reema bint Bandar Al-Saud called the deceased's family to offer her condolences.
Al Adawi's wife asked authorities to help her fulfill her husband's wish to be buried in Mecca. They have since complied with her request. The body should reach Jeddah, Saudi Arabia, on Monday at 1:40 p.m.
Before Al Adawi's body was found, the Saudi community in Kent performed a prayer in his honor at a local Islamic center.
The Saudi man had disappeared last week near the U.S. side of the Niagara Falls in New York City. He had left his wife and kids behind in the family's car to get a few photographs in the area surrounding the falls.
He was reported as a missing person by his partner hours later, given that he failed to return to his family. At the time of the incident, people started circulating a Snapchat image that allegedly captured the moment Al Adawi fell into the water.
Days after a hashtag circulated on Saudi Twitter asking people to help search for Al Adawi, another one made the rounds online, this time mourning his loss.
"Sleep well; you lived well and you'll always be in our souls, wishes, and prayers, as we knew you, a kind man who'll never die."
"May God be with his family and grant them patience"
Some had questions over the tragic case
"I am shocked by the way he fell so easily. I mean is the place unsafe or what? If anyone knows the area help us understand!"
Rest in peace
Not the first similar tragic incident to be reported in recent months
Earlier this year, another Saudi national identified as Mothker Al Subaie vanished while touring near Uganda's River Nile (White Nile).
The businessman was unfortunately found dead two days later. Authorities said he died of drowning after slipping into the river while trying to click a selfie.
At the time, officials added that the man was touring the Kalagala Falls area in central Uganda with a group of friends when the tragic incident occurred.