Under such circumstances the issue of “duress” would be raised. I would be amazed if any honest judge would EVER knowingly allow evidence acquired from any forcible means regardless of who was involved to be allowed into evidence.
It came up in the 1980’s when I was the Vice-Commander of the Army-Air Force Center for Low Intensity Conflict. I helped participated in building “agony points” for Mr. Fred Friendly. He was an old guy then and produced a show called “In the Face of Terrorism” for PBS. Friendly at one time had been president of CBS News and the creator, along with Edward R. Murrow, of the documentary television program See It Now. He originated the concept of public-access television cable TV channels. The law enforcement representative from DOJ was the one that brought the point up about the confession. Another interesting point which was used was a plane sitting on the ramp hijacked by terrorists. The terrorists ask for a reporter and camerman to come aboard the plane. During the broadcast he asked Leslie Stahl whether she would do it and she said she would “jump at the chance” to get a great story. When she gets on the plane with her camera man the terrorist say they don’t think people are taking them serious. They have a military man on his knees and execute him while she and her camera man are filming. After Friendly presented this to Stahl he asked her if she still thought the media was just the eyes and ears of the public rather than complicit in the murder. You could have heard a pin drop as she was speechless.