I have reviewed some published material on the attacks by USS Crow and Koiner at the site of the sinking of U-869. Crow reported attacking first with a "hedgehog" weapon and then following up with several attacks of ordinary depth charges. Koiner's records are not so explicit but it seems that she only dropped depth charges in attacks after Crow's.

There are two points of damage on U-869. One is a fairly large explosive point of damage near the conning tower and another is an even larger point of damage in the aft torpedo room. While an acoustic torpedo is likely to strike aft near the screws, both these points of damage are on the upper side of the sub's upper structure. The two points of damage are separated by about 75-85 feet; it is impossible for a single "circle runner" to do all of this damage. Both these points of damage catastrophically ruptured the pressure hull; either would have been fatal damage on their own. As I noted above, there was no sign of any underwater explosion not related to the firing of hedgehog or depth charge weapons.

Since Crow reported a hedgehog explosion, and both Crow and Koiner reported oil and debris rising after some of their attacks, all evidence points towards attacks by surface ships as a cause of U-869's sinking. (It would be interesting to review divers' reports as to whether any of U-869's torpedoes had been expended or if they could still be accounted for as contained in the sunken boat.)