When Associated Press journalist and Marine Corps veteran James LaPorta agreed to advise the NBC-TV show “This Is Us” about depicting the military authentically, he found more than he'd bargained for.

TV writer Jas Waters' cause of death has been disclosed. "The entire #ThisIsUs family was devastated to learn of Jas Waters passing. RIP @JasFly." RIP @JasFly." RELATED CONTENT:This Is Us Writer Jas Waters Dead at 39: Mandy Moore and Stars ReactMel Winkler, 'Devil in a Blue Dress' Actor, Dead at 78Bonnie Pointer of The Pointer Sisters Dead at 69

Jas Waters, a writer on the hit NBC family drama, has died at the age of 39. "The entire #ThisIsUs family was devastated to learn of Jas Waters passing. The entire #ThisIsUs family was devastated to learn of Jas Waters passing. She made an indelible mark on our show and my heart breaks for her loved ones. She made an indelible mark on our show and my heart breaks for her loved ones.