On Tuesday, commercial satellite imagery obtained by North Korea-monitoring website NK PRO showed boats often used by Kim had made movements in patterns that suggested he or his entourage may be in the Wonsan area.

“Extensive analysis shows that similar leisure boat movements at an exclusive villa in Wonsan and a nearby island near the Kalma peninsula have aligned with Kim’s public appearances in the area in every one of a half-dozen instances since last summer, and many more dating back to 2013,” it said.

The imagery adds to earlier satellite pictures studied by the Washington-based North Korea monitoring project 38 North, which appeared to show that a train similar to Kim’s was parked in the resort’s so-called “leadership station” reserved for the use of the Kim family a week ago.