A missing U.S. Navy sailor in Illinois was found dead along Lake Michigan's shoreline, authorities said.

According to My Stateline, Seamus Gray, 21, was last seen outside Ibiza bar in the early morning of March 18, when he and his friends were escorted out for being too drunk.

The security footage shows the missing U.S. Navy sailor walking toward Lake Michigan with at least two other persons and later walking alone but never returning to Naval Station Great Lakes.

Authorities launched a search but eventually called it off. Gray was found dead on Wednesday night. A group of ComEd utility workers, who were doing routine work near the harbor, reportedly discovered his body in the water.

The Lake County Coroner has confirmed Gray's identity, and based on preliminary autopsy results, he died from drowning.

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Security Footage Shows Last Moment of Missing U.S. Navy Soldier 

On the day following St. Patrick's Day, or on March 18, the Illinois native was spotted exiting the Ibiza nightclub on Genesee St. in Waukegan at about 1:30 a.m.

Seamus Gray was seen chatting with a group of people outside the club when one of them appeared to seize his wallet and toss it back at him. Gray is then spotted fleeing through an alley, PEOPLE reported.

Gray's disappearance was not reported to authorities until 2 p.m. on March 21. In a press conference, Ibiza manager Adrian Hernandez said Gray was removed from the club due to intoxication. He also said Gray had been in two fights in the street.

The outdoor security camera appears to have recorded at least one of those altercations. After the altercation, Gray seemed to fall to the ground. Local authorities reviewed more camera footage of Gray near Lake Michigan.

Brian Mullen, the deputy chief of police in Waukegan, said the tape showed Gray "exactly on the water's edge." Divers had reportedly searched the area but did not immediately find the missing U.S. Navy sailor.

Missing U.S. Navy Sailor's Disappearance Remains Under Investigation

In a statement, the Lake County Coroner's office said there was 'no evidence of significant injury which would have contributed" to Seamus Gray's death.

However, NBC Chicago reported that the incident remains under investigation by the U.S. Naval Criminal Investigative Service, the Waukegan Police Department, and the Lake County Coroner's Office.

Police said a "toxicology testing" is still being conducted, and it will take four to six weeks to be completed.

"On behalf of the city of Waukegan, I extend our deepest condolences to the family of Séamus Gray," Waukegan Mayor Ann Taylor said in a statement. "As a mother, I can't begin to imagine feeling the sadness and pain that Seamus' family has and will endure. Our prayers are with Mr. Gray's family."

The missing U.S. Navy sailor's unusual disappearance prompted extensive search efforts from numerous departments as investigators battled to solve the case.

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Written by: Bert Hoover

WATCH: Cause of Death Revealed for Missing U.S. Navy Sailor Found in Lake Michigan - From Fox 32 Chicago