The maximum likelihood procedure for estimation of source location parameters in a multipath medium using a passive array of point sensors is presented. The maximum likelihood estimation procedure is explained in terms of combined focused beamformer operations on each multipath arrival. An approach to the adaptive realization of the multipath focused beamformer is given which exploits an orthogonal decomposition of the estimated spatial cross-spectral density matrix (CSDM) of the array. An example from passive sonar array processing is given.