Justice is an interesting thing, I came across this case and had to boil down everything I read into this simple synopsis:
US Army Master Sgt Timothy Hennis was convicted in 1986 of murdering his wife and her two daughters in a North Carolina state court. This conviction was overturned because of weak evidence and improper statements by the prosecution, he was acquitted unanimously at his 1989 retrial, returned to the army and retired in 2004. Case closed right?
Evidence from the crime scene was preserved and screened when DNA testing became available, and strongly indicated that Hennis really was guilty of the murders. Double jeopardy, (oft quoted but little understood,) prevented a new trial in a North Carolina court; but, Hennis was returned to active duty from his retired status and tried by court martial under military law. He was found guilty and is now back on death row 20 years after his acquittal.
The separate legal systems, state and military in this case, allow a retrial even if the accused is acquitted in state court. (Similar to what happened to the cops in the Rodney King Case, state versus federal jurisdictions and statutes.)
He had been listed on the Death Penalty Information Center's list of prisoners from death row later found to be innocent. Interesting thing though, the Death Penalty Information Center carefully omits that the victims were his wife and her young daughters, just calling them three people. Another site refers to the victims as a woman and her daughters.
Interesting side note, a TV movie was made about his case in the 90s with the tagline "It Could Happen to You," I guess the tagline for the follow-up could be "Karma's a Bitch." Speaking of movies, if anyone saw "Double Jeopardy", she really could be tried for killing the same guy twice, even if he faked his death the first time.