Lizourn fell into the river just north of the Ben Franklin Bridge. He was last spotted about 100 yards off shore and about 100 yards north of the Ben Franklin Bridge on Wednesday night.
The Coast Guard has been searching for him since then.
It was around 10:30 p.m. when Lizourn's son called 911 to say his father fell in the water.
He was wearing dark clothing, making it difficult to spot him on the nighttime water.
Authorities released a picture of Lizourn in case he made it to shore, but became disoriented.