Up in smoke...

I am repairing my neighbor's girlfriend's car amp (MTX Thunder250D) and I need either a schematic or a cross reference part number. Whenever it is turned on two of the MOSFETS go up in smoke (connected in parallel). The parts are i think a TO-220 package and they have this written on it:

HO 27

The manufacturers logo is unrecognizeable because of the heat. Both FETs blew out the same leg. I called digi-key and all they could come up with is a Harrison MOSFET but they couldnt confirm an exact match. Thanks!