The unidentified person who crossed the heavily guarded border into North Korea on New Year’s Day was “presumably” a high-profile defector who previously crossed into South Korea around a year earlier, according to Seoul’s Ministry of National Defense (MND) on Monday.

But a ministry official denied that the redefector was a DPRK spy, after South Korean authorities detected four individuals from North Korea near the demilitarized zone (DMZ) following the border crossing. The ministry said it can’t “specify” that they were there to pick up the border crosser, but that the person did not have a job that would give them access to sensitive information.