Doris Allen, an Army intelligence analyst during the Vietnam War whose warning in early 1968 about the impending attacks by North Vietnamese and Vietcong forces that became known as the Tet offensive was ignored by higher-ups, died on June 11 in Oakland, Calif. She was 97.

Her death, in a hospital, was confirmed by Amy Stork, chief of public affairs for the Army Intelligence Center of Excellence.

Specialist Allen, who enlisted in the Women’s Army Corps in 1950, volunteered to serve in Vietnam in 1967, hoping to use her intelligence training to save lives. She had been the first woman to attend the Army’s prisoner of war interrogation course and worked for two years as the strategic intelligence analyst for Latin American affairs at Fort Bragg, N.C., now Fort Liberty.

Working from the Army Operations Center in Long Binh, South Vietnam, Specialist Allen developed intelligence in late 1967 that detected a buildup of at least 50,000 enemy troops, perhaps reinforced by Chinese soldiers, who were preparing to attack South Vietnamese targets. And she pinpointed when the operation would start: Jan. 31, 1968.

In an interview for the book “A Piece of My Heart: The Stories of 26 American Women Who Served in Vietnam” (1986), by Keith Walker, Specialist Allen recalled writing a report warning that “we’d better get our stuff together because this is what is facing us, this is going to happen and it’s going to happen on such and such a day, around such and such a time.”

She said she told an intelligence officer: “We need to disseminate this. It’s got to be told.”

But it wasn’t. She pushed for someone up the chain of command to take her report seriously, but no one did. On Jan. 30, 1968 — in line with what she had predicted — the enemy surprised American and South Vietnamese military leaders with the size and scope of their attacks.