With Chief Eddie Gallagher’s court martial underway, a SEAL medic made a stunning confession when he took the stand today.

Navy SEAL Chief Eddie Gallagher stands trial for the murder of a teenage ISIS detainee in Mosul, Iraq — allegedly killing him with a knife. However, Special Warfare Operator 1st Class Corey Scott changed his story on the stand today during cross-examination, saying that in fact it was he who killed the detainee. Scott claims that while Gallagher did stab the teenager with a knife, that his condition was stabilized and he and Gallagher had provided medical treatment. Scott then claims that he put his thumb over the air tube he had inserted into the detainee’s mouth, which asphyxiated and killed him. The SEAL medic said he did this because he had seen Iraqi Emergency Response Division (ERD) soldiers torture and rape detainees in the past, and so suffocating him to death was a type of mercy killing.

According to a Fox News report, the prosecution became quite flustered as this statement contradicted previous statements that Scott had given to investigators. Scott now has immunity from prosecution, granted in exchange for his testimony. The lead prosecutor stated to him while on the stand, “You can lie about the fact that you killed the ISIS prisoner because you don’t want Chief Gallagher to go to jail.” Scott confirmed that he did not want Gallagher to go to jail.

More witnesses are expected to take the stand today, but at this point it is possible that the defense simply requests an acquittal.