Investigators are looking for four men who flew out of Malaysia the same day the North Korean ruler's exiled half brother, was apparently poisoned at an airport in Kuala Lumpur.
Since Kim Jong Nam's death last week, authorities have been trying to piece together details of what appeared to be an assassination.
Malaysian police have so far arrested four people carrying IDs from North Korea, Malaysia, Indonesia and Vietnam.
One of the suspects in custody, an Indonesian woman, told investigators that she was duped into thinking she was part of a comedy show prank.
On Sunday, Malaysia's deputy national police chief, Noor Rashid Ibrahim, said four more suspects were on the run. The men were North Korean and had flown out of the country last Monday, when Kim died.
"I am not going disclose where they are," he \a news conference, adding that Interpol was helping with the investigation.
He showed photographs of the four men, who were travelling on regular passports and are aged 33, 34, 55 and 57.
He also said there were three other people police wanted to question.
Kim Jong Nam, 46, was waiting for his flight home to Macau when, authorities say, he was set upon by two women.
He sought help at a customer service desk and said "two unidentified women had swabbed or had wiped his face with a liquid and that he felt dizzy", Mr Noor Rashid said.
Kim died en route to a hospital after suffering a seizure, officials say.
Mr bNoor Rashid said that he expected post-mortem examination results to be released within days.
"We have to send a sample to the chemistry department, we have to send a sample for toxicology tests," he said.
Investigators also want to speak to Kim Jong Nam's next of kin to formally identify the body. He is believed to have two sons and a daughter with two women living in Beijing and Macau.
"We haven't met the next of kin," Mr Noor Rashid said. "We are working, we are trying very hard to get the next of kin to come and to assist us in the investigation."
The case has raised tensions between Malaysia and North Korea. Pyongyang demanded custody of Kim's body and strongly objected to the post-mortem.
The Malaysians went ahead anyway, saying they were simply following procedure.