Kim Jong-nam may have done himself in through his Facebook postings about his whereabouts.
"Open activities like these do not look like they are coming from a person who is constantly under death threats.
"I think it is possible that Kim (Jong-nam) was careless, leading to his ... death," said Cha Du-hyeong, former intelligence secretary to South Korean President Lee Myung-bak, as quoted in NK News.
NK News, which focuses on North Korean news, reported that an FB account belonging to one "Kim Chol" contained past pictures of Jong-nam in Macau.
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(Kim Chol was also the name stated in the passport of the North Korean man killed on Monday at KLIA2, now confirmed to be Jong-nam.)
NK News, quoting an unnamed source familiar with Jong-nam's online activities, confirmed that the Facebook profile was indeed that of Jong-nam.
The news site shared a screenshot of the Facebook page, showing pictures of Jong-nam in Macau where he lived in self-exile and where he was believed to be heading to before he was bumped off.
The portal reported that Jong-nam's activities on his Facebook page seemed to indicate that he was not trying to hide from public view and that he could not stay away from social media even when he was hunted.
In one photo posted in October 2008, Jong-nam was standing on a yacht with an unidentified male Caucasian. On March 4, 2013, he commented on this post, saying "I miss Europe!"
"Nice place!" Jong-nam said of another image uploaded in 2010 in which he is standing in front of the five-star Wynn Macau hotel.
The profile picture on the Kim Chol account is not of Jong-nam but that of a squirrel.
His most recent visible activity was in November 2015 when he temporarily set his profile picture to the French flag filter in solidarity with the victims of the Paris attacks.
Other information available on his profile page included his education background, which stated that he studied at the International School of Geneva and at the Lycee Français de Moscou (Alexandre Dumas French School in Moscow).
Jong-nam was previously reported to have spent most of his youth at these two schools.