Sad news to report. According to Comic Book Resources' Robot 6 blog, picking up on a report from Mark Evanier, comic book artist and animator Ric Estrada has died after a lengthy battle with cancer. He was 81. From Robot 6's obit:

Estrada was perhaps best known for his work on Amethyst: Prince of Gemworld, Karate Kid, Superboy & the Legion of Super-Heroes and numerous DC war comics, including G.I. Combat, Our Army At War, Weird War Tales and Unknown Soldier. Later in his career, he moved into animation with such 1980s TV series as He-Man and the Masters of the Universe, Jonny Quest and Bionic Six.
DC Comics President and Publisher Paul Levitz shared his thoughts on Estrada's life and work: "Ric was a quintessential cartoonist, storyteller and animator, ready to take on any material or creative challenge with a smile," Levitz said. "He'll be remembered for tales he told, lessons imparted, and for his abundant love of his life, his family and his faith."