A military court in California cleared Edward Gallagher, 40, Tuesday of the murder of a teenage Islamic State group prisoner in 2017 in Iraq as well as other serious charges related to the case.

Gallagher was found guilty only of posing with the slain fighter's body in a group picture with other SEALs, a charge that carries a much lighter sentence.

Trump, who had previously suggested he might pardon Gallagher if he were convicted, hailed the verdict in a tweet.

"Congratulations to Navy Seal Eddie Gallagher, his wonderful wife Andrea, and his entire family. You have been through much together. Glad I could help!" he wrote.

Gallagher was expected to walk free on the basis of time served.

The military court Wednesday demoted Gallagher by one rank, from chief petty officer to first class petty officer -- a penalty that will reduce his salary and pension.

Spurred on by his wife, a group of lawmakers had lobbied for his release in an initiative publicized by the conservative Fox News network.

The prosecution's case was dealt a major blow when a witness said that it was he, not Gallagher, who had put an end to the captive IS militant's life.

Corey Scott, a first class petty officer, testified that while he had seen Gallagher stab the wounded fighter in the neck in May 2017, he had killed the boy afterwards.

He testified that he covered the victim's breathing tube with his thumb and then watched him die.

Scott said he did so to spare the boy -- who prosecutors say was about 15 years old -- from suffering or being tortured by Iraqi forces.

Scott, who was given immunity from prosecution, acknowledged during questioning that he made the revelation to spare Gallagher, who is married and has children, from going to prison.

Prosecutors argued Scott's version of events was a fabrication and that he was lying to protect Gallagher.