Our research consists of a near-IR astrometric and spectroscopic study in which we search for substellar objects orbiting nearby white dwarfs (WDs). Our purpose is to test specific predictions of the common envelope evolutionary phase, as well as to provide constraints to planetary system evolution in advanced stages of its parent star. Observations in near-IR allow us to reach the detection limit of giant planets by taking advantage of the diminished brightness contrast between the primary \& secondary objects. First epoch observation in near-IR imaging on a carefully selected sample of WDs within 20 pc of the Sun has produced a list of several extra-solar and brown dwarfs candidates to these nearby WDs. 2nd observation epoch will allow the confirmation (through common proper motion) of sub-stellar objects down to $\approx 5 M_{Jupiter}$ among post-main sequence stars. In addition, high S/N near-IR spectroscopic observations were obtained for WDs in this sample, with the goal to detect spectroscopic signatures of unresolved substellar objects orbiting a WD. Preliminary results of this project will be shown.