We calculate resonances in three-body systems with attractive Coulomb potentials by solving the homogeneous Faddeev-Merkuriev integral equations for complex energies. The equations are solved by using the CoulombSturmian separable expansion approach. This approach provides an exact treatment of the threshold behavior of the three-body Coulombic systems. We considered the negative positronium ion and, besides locating all the previously know S-wave resonances, we found a whole bunch of new resonances accumulated just slightly above the two-body thresholds. The way they accumulate indicates that probably there are infinitely many resonances just above the two-body thresholds, and this might be a general property of three-body systems with attractive Coulomb potentials. PACS numbers: 34.10.+x, 02.30.Rz The most common method for calculating resonant states in quantum mechanical systems is the one based on the complex rotation of coordinates. The complex rotation turns the resonant behavior of the wave function into a bound-statelike asymptotic behavior. Then, standard bound-state methods become applicable also for calculating resonances. The complex rotation of the coordinates does not change the discrete spectrum, the branch cut, which corresponds to scattering states, however, is rotated down onto the complex energy plane, and as a consequence, resonant states from the unphysical sheet become accessible. By changing the rotation angle the points corresponding to the continuum move, while those corresponding to discrete states, like bound and resonant states, stay. This way one can determine resonance parameters. In three-body systems there are several branch cuts associated with two-body thresholds.In practice, the complex rotational technique is combined with some variational approach. This results in a discretization of the rotated continuum. The points of the discretized continuum scatter around the rotated-down straight line. So, especially around thresholds it is not easy to decide whether a point is a resonance point or it belongs to the rotated continuum. Moreover, variational methods approach states from above, so resonances slightly above the thresholds may easily get lost.Recently, we have developed a method for calculating resonances in three-body Coulombic systems by solving homogeneous Faddeev-Merkuriev integral equations [1] using the Coulomb-Sturmian separable expansion approach [2]. As a test case, we calculated the resonances of the negative positronium ion. This system has been extensively studied in the past two decades and thus serves as test example for new methods. We found all the 12 S-wave resonances presented in Ref. [3] and observed good agreements in all cases.We also observed that in case of attractive Coulomb interactions the Faddeev-Merkuriev integral equations may produce spurious resonances [4], which are related to the somewhat arbitrary splitting of the potential in the three-body configuration space into short-range and long-range terms. We could single them out by changing t...