  The gravitomagnetic monopole is the proposed gravitational analogue of
Dirac's magnetic monopole. However, an observational evidence of this aspect of
fundamental physics was elusive. Here, we employ a technique involving three
primary X-ray observational methods used to measure a black hole spin to search
for the gravitomagnetic monopole. These independent methods give significantly
different spin values for an accreting black hole. We demonstrate that the
inclusion of one extra parameter due to the gravitomagnetic monopole not only
makes the spin and other parameter values inferred from the three methods
consistent with each other but also makes the inferred black hole mass
consistent with an independently measured value. We argue that this first
indication of the gravitomagnetic monopole, within our paradigm, is not a
result of fine tuning.
