Thousands of friends and family members gathered in suburban Cincinnati on Thursday to say goodbye to an American student, Otto Warmbier.
South Korea has said the North bore responsibility for Warmbier's fate and US President Donald Trump has slammed his detention and eventual death as "a total disgrace".
He was traveling in North Korea with a tour group and was arrested at Pyongyang airport as he was about to leave.
After he returned to OH, doctors determined he had suffered a "severe neurological injury" of unknown cause.
Warmbier, a 22-year-old University of Virginia student, died Monday, six days after he returned to his OH home in a coma after 17 months of detention in the North for taking down a political propaganda sign from a hotel.
His family blamed the "awful torturous mistreatment our son received at the hands of the North Koreans".
He was serving a sentence of hard labor after being accused of stealing a propaganda poster.
Kenneth Bae, an American who was jailed for almost two years in North Korea, told CNN he believed Warmbier could have been tortured, and cautioned other Americans against going to North Korea. The report did not mention Warmbier's neurological status. The attendees included Ambassador Joseph Yun, the US special envoy who traveled to Pyongyang to bring Warmbier back.
"To make it clear, we are the biggest victim of this incident and there would be no more foolish judgment than to think we do not know how to calculate gains and losses", the spokesman said.
"The smear campaign against (North Korea) staged in the USA compels us to make firm determination that humanitarianism and benevolence for the enemy are a taboo and we should further sharpen the blade of law", the spokesman added.
Washington has also stepped up its muscle-flexing in the region, flying two B-1 bombers over the Korean peninsula Tuesday in a planned training mission with Japan and South Korea as its latest show of force.
The exact cause of Mr Warmbier's death is unclear.
"Let us state the facts plainly: Otto Warmbier, an American citizen, was murdered by the Kim Jong Un regime", said U.S. Sen.
It demanded that South Korea return 12 restaurant workers who defected to the South a year ago.
"When I was organizing the trip and I (met) with the delegates here, I addressed Otto Warmbier and I said to them we would need some type of good faith if we're ever going to do some type of future sports relations".
That was because the North Korean justification for his imprisonment centered on a dubious claim that Warmbier had stolen a propaganda poster in a Pyongyang hotel lobby on orders from the Friendship United Methodist Church in Wyoming, Ohio, to bring it back "as a trophy" in exchange for a used auto worth $10,000.
The North Korean representative also faulted Obama's policy of "strategic patience".