Magnet fishers found what appeared to be a bomb on March 2 and an unexploded "bazooka" round on March 6 while casting from the Kendrick Street Bridge, CBS Boston reported. Both items were very deteriorated as if they had been there for years.
A CBS news team was with the magnet fishers when they pulled the rocket round from the water.
State Police Lt. Sean Quirk told CBS that he wouldn't be surprised if there were more unexploded ordinance down there. That concern initiated Monday's search.
State dive teams used underwater drones to search for anything else hiding on the river bed.
They pulled a long tank containing an unknown substance from the water, but it was later determined to be not hazardous. Needham Public Works employees disposed of the tank.
Click here to follow Daily Voice Quincy and receive free news updates.