The only North Korean national arrested so far in connection with Mr Kim Jong Nam's murder has been in Malaysia since 2013 on a work visa arranged by healthcare medication company Tombo Enterprise.
Mr Chong Ah Kow, the owner of the company in Kuala Lumpur, admitted helping Ri Jong Chol, 46, to get the work visa, but said Ri was not an employee.
Information released by Malaysian police described Ri as an employee in the IT department of Tombo Enterprise, and said his official employment pass had expired on Feb 6, a week before Mr Kim died last Monday. "I treated him as a businessman," Mr Chong told reporters, adding that he had met Ri only five times in the past three years.
He said Ri was a business associate who was interested in the import export business and needed a visa to operate in Malaysia.
While Ri had expressed interest in setting up an IT business locally, Mr Chong said he had no further knowledge about his activities.
He said he had "a shock" when he heard of Ri's arrest.
Mr Chong told reporters that he was introduced to Ri by the latter's uncle, named Mun Ho, a scientist in North Korea specialising in mushroom extract.
He was also asked to help Ri, who was purportedly interested in importing and exporting palm oil and herbal extracts.
A report by North Korea's Korean Central News Agency said a scientist by the name of Dr Mun Ho had developed a health product made from mushroom, known as "jangmyong".
Mr Chong said though he and Ri had explored business opportunities in health products, nothing materialised because they were unable to agree on pricing.
He said his contact with Ri was mostly through messaging apps. Also, when Ri needed his help to find business contacts in Malaysia, Ri's daughter, a student at the private HELP University in Kuala Lumpur, acted as translator.
Ri, from Pyongyang, graduated in science and medicine from a North Korean university in 2000, according to a report in The Star. He did research at a centre in Kolkata, India, for about a year until 2011. He then returned to Pyong- yang before going to Malaysia.
Japanese daily Yomiuri Shimbun said Ri is believed to be a member of North Korea's foreign intelligence service, according to a South Korean government source.
North Korea's Ambassador to Malaysia, Mr Kang Chol, has described the arrest of its citizen as "forcible" and carried out "without any warrant or evidence".