Are retirees subject to UCMJ?

Not only are you subject to but , you are also called back for appeals and restoration as well

I would think yes, for a crime that was committed while on active duty with no statute of limitations like murder.

That MSG is currently on death row at leavenworth. Timothy Hennis is his name.

Hahahaha..... if yoi get paid. MEB baby and fuck the Army weeny lol

Of course the military can do what ever they never really let go.

Think they just did this to army general.....

I have been retired since 1971. I seem to remember being told that retirees can be tried only for acts of treason or spying by UCMJ. Any other crime to be tried by civilian authorities. http://www.vfwwebcom.org/forum/index.php?topic=10740.0

Yes, and yes, and no. You can be called back for criminal behavior performed before leaving, you can be called back for criminal behavior after leaving(in paid retirement), or you can be called back for espionage. Cue the music! "Learning and growing!"

Retirees vs separated members are two different things. The UCMJ has no authority over separated members unless the offense occurred while the member was still under military jurisdiction.
In cases of separated members say selling defense secrets to China or something, the offender would likely be handled by civilian channels and prosecuted under the National Defense Espionage Act. Investigated by the FBI, and tried in a US District Court.

I wouldn't worry about it. During my tenure with the Riverside County Sheriffs Department, I found the military was not the least bit concerned with the off duty antics of their active duty personnel.