While divers plumbed the depths of the river's brackish waters, other searchers combed the river banks, The Baltimore Sun reported.
The volunteer organization Texas Equusearch had said Sunday its sonar detected what appeared to be a body but divers failed to find one, the newspaper said.
The (New Orleans) Times-Picayune reported searchers were focused on a spot less than a mile downriver from where a man thought to be Brian Reed, 29, leaped into the water Jan. 7 after fleeing from police in a stolen vehicle.
The Reed family brought in Texas Equusearch Wednesday and the group's sonar showed an image of what was thought to be a body surrounded by debris in about 15 feet of water. A diver failed to locate anything and became briefly tangled in the debris.
Tim Miller, founder and director of Texas Equusearch, said the river's current may have swept the body away.
"We're not going to quit until we find him or until we get to that point where we've used up every resource," Miller said.
Reed's family, including Ed Reed, arrived at the scene when it was reported that a body had been found.
Ed Reed declined to comment but Brian Reed's sister-in-law, Javona Sanchez, said: "We just want some closure at this point. We wanted him back regardless."