In two new dispatches on Thursday morning, the North's state-run KCNA news agency said Kim went to Pyongyang's station on Wednesday evening "to see off a special objective train carrying the bodies of Chinese who were killed and the wounded in a tragic traffic accident".
It's also not clear how the leaders will announce the results of the summit.
The profile will also include intelligence gathered in past debriefings of others who have interacted with Kim, including ex-NBA star Dennis Rodman, Kim's former classmates at a Swiss boarding school and South Korean envoys, other US officials said, speaking on condition of anonymity.
Ahead of their talks which will begin at 10:30 a.m., Moon and Kim will meet an hour earlier at Military Demarcation Line (MDL), that divides the two Koreas.
After the welcoming ceremony, the two leaders will move on foot to the Peace House, a venue for the third inter-Korean summit since the first in 2000 and the second in 2007 were held in the DPRK's capital of Pyongyang.
When Kim first came to power, the Central Intelligence Agency predicted that Kim's rule might be short-lived. Later in the year, Chung led 501 more cows to the DPRK.
The North's nuclear arsenal will be high on the agenda.
The emerging USA consensus on Kim is similar to what many outside experts have publicly concluded. Local authorities will assist families of the victims, Hua said. In terms of personality, he is seen more like his charismatic grandfather, Kim Il Sung, than his more camera-shy father.
Shielded by North Korea's extreme opaqueness, Kim has posed a special set of profiling problems for US spy agencies.
South Korean Foreign Minister Kang Kyung-hwa seemed to indicate that Seoul won't raise at the summit what the United Nations says is Kim's pattern of starving and abusing his people, despite being pressed by activists to do so, when she told reporters that to "include the (human rights) issue in the inter-Korean dialogue now is something that will require more preparation".
"(Kim Jong-un's entourage) includes core military and diplomatic officials, which was not expected", said Im Jong-seok, President Moon Jae-in's chief of staff and head of the summit preparation committee.
The information the world receives will also be closely controlled: Except for a group of pool reporters at the summit, whose access may be extremely limited, journalists will be sequestered at a media center well away from heavily guarded Panmunjom, the border village where the summit will take place. A banquet and farewell ceremony will follow in the evening before Mr Kim returns to the North.
"But in order for its policy to work, the government must open its ears to various voices on North Korea", the conservative Korea JoongAng Daily recently wrote.
"Perhaps the North Korean nuclear weapons problem can be solved through dialogue", said Seong Sun-gi, a 53-year-old Seoul housewife.
A White House official declined comment on the episode.