RedactedNarrative: On 06-22-14 at 3:41 pm I was notified by CPO that a single vessel boat accident occurred on the Illinois River at Dresden Island Lock and Dam in which one of the four occupants from this vessel was missing. I arrived on scene at 4:17pm and witnessed multiple Fire/Rescue agencies attempting to rescue a male subject from the bow of Vessel #1 (IL 0142 GX) which was lodged between the bottom of tainter gate #8 and the concrete base of Dresden Island Lock and Dam. Coal City Fire Chief advised the accident occurred at 3:27 pm and there were four people in Vessel #1 before it struck tainter gate #8. Chief further advised two occupants were rescued by unknown pleasure boaters immediately downstream of the Dam and one occupant was still missing. 
   
  Operator was rescued from Vessel #1 at 4:43 p.m. and I spoke with him briefly before he was transported to Morris Hospital for examination. I asked him if he was the operator of the boat(Vessel #1). Operator advised he was. I asked him to describe what happened. Operator advised himself, Occupant1(his wife), Occupant2(his son) and Occupant3(son''s girlfriend) were boating on the river near the mooring cells located approximately 200 yards upstream of the Dam when some tree branch debris became lodged between the boat''s lower unit and stern. He advised he turned the motor off and raised the propeller freeing the debris. Operator advised he lowered the propeller back into the water and tried starting the motor repeatedly with no success. He advised the current was drifting them towards the Dam so he threw out his anchor from the bow of the boat which did not stop them. Operator advised Occupant1, Occupant2 and Occupant3 (each possessing a Type IV P.F.D.) jumped from the rear of the boat in attempts to swim to safety when they were approximately 30-40 yards upstream of the gate(tainter gate #8) they were drifting to. Operator advised he stayed on the boat''s(Vessel #1) bow when it struck the gate and became wedged between the gate and bottom. Operator advised the back(stern) of the boat struck the gate first. He advised he witnessed Occupant3 pass by him through the gate and attempted to grab her unsuccessfully. I asked Operator if he had any wearable P.F.D.''s on board. He advised no, just the throwable P.F.D.''s. operator, Occupant1 and Occupant2 sustained no physical injuries from this boat accident. On 06-25-14 at approximately 11:45 a.m., the body of Occupant3 was located by Morris Fire and Rescue personnel south of Grist Island at river marker 258.6 on the south river bank. On 06-25-14 at 3:00 P.M., Grundy County Coroners Office performed an autopsy on Occupant3. On 07-16-14, autopsy final results found Occupant3 cause of death was drowning. Her death was ruled accidental and toxicology results found no alcohol/drugs in her system.