Detection of the near-infrared counterpart of GRB 971214 3.2 hours after the gamma-ray event

We report the detection of the GRB 971214 counterpart in the near-infrared by means of two images in the K′-band taken at Calar Alto only ∼3.5 and ∼5 hours after the gamma-ray event. We detect the transient at K′=18.03 ± 0.18 and K′=18.00 ± 0.22 respectively. Our data seem to indicate the existence of a plateau with duration 1.5 ≤ T ≤ 6.7 hours (between 3.5 and 10.2 hours after the high-energy event). Moreover the power-law decline should be steeper than the one given by the index αK′ = 0.45. There is also a change in the slope of the broad-band spectrum at some wavelength between the J and K′ bands (possibly around the H-band).