He has also appeared more accessible and open than his father, hugging and linking arms with young and old.
Two women accused of killing Kim have said they thought they were.
On 19 February, Malaysian police named four more North Korean suspects.
According to lawyer Hisyam, Thủy also turned down efforts by Vietnamese police and defence lawyers to travel to Malaysia to testify for Hương, citing her responsibility in running her bar with her husband and taking care of her young child.
In Washington, there was no immediate response to a request for comment from the Trump administration, which faces a stiff challenge from a defiant North Korea over its nuclear arms program and the test of a ballistic missile last weekend.
For several hours on Wednesday evening, four police vehicles and around a dozen officers, some armed, were nearby.