It is easy to calculate the radar horizon given height above ground for antenna and target.
Obvious assumptions in this case at 37,000ft (FL370) and radar at 15ft. This gives a theoretical range of 236 nms.
These assumptions are probably incorrect and unless your perpetrator was sufficiently knowledgeable a 3 minute (23 mile) gap between leaving radar cover (225 miles) and restoring power would be too close or ineffective.
In reality FL370 would be nearer 39,000ft in the tropics. That gives a radar horizon of 241 nms.
Then there is a property known as anaprop or anomalous propagation where the radar bends and goes further over the horizon.
Now in this instance we know the last radar contact fell well below the theoretical ranges. Did this mean the aircraft was at 32,000 feet or that the radar performance was well below optimum?
I submit therefore that for there to be a deliberate masking until beyond the radar horizon and resumption of power 3 minutes later was unlikely the timing was too tight for the probable variations in range but just pure coincidence.