North Korea's public executions tend to happen near rivers, in fields and on hills and also at marketplaces and school grounds - places where residents and family members of those sentenced are often forced to attend the killings, the report said.
"There was a nexus" between the Central Intelligence Agency and Kim Jong nam, The Wall Street Journal quoted the person as saying.
Kim Jong Nam, who was once seen as heir apparent to the North´s leadership, died after having his face smeared with the outlawed VX nerve agent as he waited at Kuala Lumpur airport.
"That would not happen under my auspices", Trump said. "I can't show you the letter, obviously, but it was very personal, very warm, very nice letter", Trump said.
His comments represented the latest in a series of instances in which he has appeared to be at odds with the USA intelligence community. The CIA declined to comment on the claim.
The new report said its findings show arbitrary executions and extrajudicial killings under state custody have continued under the rule of young leader Kim Jong Un despite worldwide criticism over how North Korea supposedly applies the death penalty without due judicial process.
"There is a limit to the DPRK's patience", it said, using the acronym for the North's official name, adding: "Now is the time for the United States to roll back its hostile policy".
The CIA has created a Korea Mission Center that works to track North Korea's ballistic missile and nuclear weapons programs, according to an announcement from the agency in May 2017. Trump and Kim last met early this year in Hanoi but failed to reach a denuclearisation agreement. A new book attempts to pull back the curtain of opacity as it examines the country's leader, Kim Jong Un, who took over from his dictator father when his older brother fell out of favor.
President Donald Trump speaks to reporters before departing for a trip to Iowa, on the South Lawn of White House, Tuesday, June 11, 2019, in Washington.
Trump and Kim continued to express "trust in each other" and "desire for dialogue", he said. Add North Korea as an interest to stay up to date on the latest North Korea news, video, and analysis from ABC News. Relations between the two countries have been historically hostile.
"I don't know, I have not heard about that", the president said, before contradicting himself and assuring Kim Jong Un that his administration wouldn't do anything so underhanded.
Vietnamese national Doan Thi Huong (L), 28, is escorted with a heavy police presence for her alleged role in the assassination of Kim Jong-Nam, the half-brother of North Korean leader Kim Jong-Un.