The South Korean Coast Guard said the missing official shot and killed by North Korea last week was trying to defect when he crossed the Northern Limit Line, the de facto inter-Korean maritime border.
In its intermediate findings released Tuesday, the Coast Guard pointed to the fact that the man was wearing a life jacket when he was found in North Korean waters.
This was cited as a key reason as to why the incident is not seen as an attempt to commit suicide and that he was in the water deliberately.
"North Korea was aware of the man's name, age, height and hometown and circumstances showed the official had expressed his intent to defect to the North."
The brother of the deceased said authorities did not do enough to save him or discover the truth behind what happened.
"During some 30 hours of my brother crossing over to North Korea authorities lost precious time by not doing all they can to save his life. They've hastily concluded that he had tried to defect based on the eavesdropping of an enemy state and frame him of a crime."
The Coast Guard and the Navy continued their search for the man's body and his belongings for the ninth day on Tuesday.
Some 40 vessels and seven aircraft have been mobilized near the NLL.
Seoul's defense ministry said it's sticking to its initial view the North burned the body of the official after shooting him but that it's examining related material on the different accounts offered by the North.
In a notice sent by the regime's United Front Department last Friday the description of the incident suggested North Korea did not burn the man's body after the shooting but just the items he had with him.
Kim Ji-yeon, Arirang News.