Divers initially began the search for Grigor Khacheryan and his 86-year-old brother Minas Khacheryan, who live in Glendale, at about 2:30 p.m. Saturday, sheriff's Deputy M. Chen told City News Service.
The brothers' last known whereabouts was fishing at the aqueduct Friday.
PREVIOUS COVERAGE: Deputies end search for missing Glendale brothers on fishing trip
Minas' body was found Monday near 195th Street West and West Avenue G and positively identified, according to the Los Angeles County Sheriff's Department.
The investigation continued early Tuesday morning at 280th Street West and West Avenue C to 234th Street West and West Avenue D-15. Searchers included personnel from the sheriff's Emergency Services Detail and the Homicide Bureau, who resumed their efforts after daybreak.
Approximately two dozen divers were utilizing sonar, and the aqueduct water flow was controlled to facilitate the search for Grigor Khacheryan, authorities said.
Later Tuesday, the department said the investigation concluded near 195th Street West and West Avenue G.
"Despite their efforts, Deputy personnel were unable to locate the missing person, Grigor Khacheryan. Additional searches may occur pending additional information," the Sheriff's Information Bureau said in a statement.
Foul play is not suspected.