Hattori et al have recently reported the discovery of a massive cluster of 
galaxies that is bright in X-rays but dark optically. Optical and K searches of 
the cluster have reached the magnitude limits for normal galaxies without 
detecting any cluster members. Either the objects are very faint or they are 
obscured by dust.

We propose deep CAM observations of this cluster throught two ISOCAM filters to 
try and detect any cluster members.