According to TMZ, a landlord found Young's body, which had what appeared to be a self-inflicted gunshot wound.
NBC News published the following statement from Young's manager:
"It is with great sadness that I announce that Lee Thompson Young tragically took his own life this morning," Jonathan Baruch said. "Lee was more than just a brilliant young actor, he was a wonderful and gentle soul who will truly be missed. We ask that you please respect the privacy of his family and friends at this very difficult time."
When the actor didn't show up for work on Monday -- he appears on TNT's "Rizzoli & Isles" -- staff called his landlord who found him dead in his L.A. home.
More details will follow as this story develops.