Biometric detection of a fingerprint is provided by a flexible sensor, in which one or more positioning members move at least a portion of the sensor to conform to a shape of a finger disposed along the sensor to enable capture of a rolled-equivalent fingerprint for the finger. Such one or more positioning members move the sensor causing it to curl at least along a region extending between right and left sides of a fingernail of the finger around a front of the finger in order to conform the sensor to the finger so that the sensing elements of the sensor when enabled capture images of the rolled-equivalent fingerprints without rotation or rocking of the finger with respect to the sensor. When sensing elements are optically sensitive, one or more light sources may provide light to illuminate the finger when the sensor captures rolled-equivalent fingerprint images.