VERSAILLES, Mo. -

Following a coroner's inquest Thursday, a jury has ruled the drowning death of an Iowa man to be accidental after he fell overboard while in Missouri State Highway Patrol custody in May at the Lake of the Ozarks.

20-year-old Brandon Ellingson from Clive, Iowa went overboard May 31 while wearing handcuffs in the Highway Patrol Boat. Evidence revealed at a coroner's inquest Thursday showed Ellingson had cocaine and alcohol in his system at the time of his death. He was being transported on suspicion of boating while intoxicated.

Following the recommendation by the jury, Ellingson's father, Craig Ellingson, told ABC 17 News, "I was really disappointed at the outcome just based on the pure fact that he handcuffed him first and then put a life jacket over the top of him, that's negligence."

All patrol boats are equipped with a camera. But on Thursday it was also discovered an SD card was not in the camera at the time, after an earlier arrest.

Sergeant Paul Reinsch of the Missouri State Highway Patrol said Ellingson was sitting to the left of the trooper who was driving the boat. Ellingson then stood up, took a few steps back and made it to the opposite side of the boat. At some point, Ellingson's life vest came off. Reinsch was not sure if it came off immediately after he fell into the lake.

Jim Bascue was driving a water taxi when he saw the Patrol boat trying to rescue Ellingson. Bascue tried throwing a buoy to Ellingson. After a while, Bascue said his life vest came off. That is when the trooper jumped into the water to save him.

"After the subject fell into the lake, the trooper first tried to retrieve him, and then actually go into the water to rescue him, and wasn't able to do so," Reinsch said.

In an interview, one of Ellingson's friends explained seeing the officer do an eye test, handcuff Ellingson, then slip over his head an already buckled life vest.

Highway Patrol Trooper Anthony Piercy went before the jury Thursday afternoon and admitted to not having enough training on water rescues and what life vest to use on a suspect. The life vest used on Ellingson is not the one recommended to transport handcuffed people in.

Piercy went into detail about how he tried to save Ellingson with a pole and then jumped in after him, though he was not successful in deploying his own life vest and holding Ellingson at the same time.

Ellingson's body was found in the Gravois Arm at the 3.5 mile marker of the main channel. The Associated Press reports Ellingson was attending Arizona State University. According to the school's online directory, he was enrolled as a business student.