This sounds similar to the article you describe:
POW Drive in Confusion
(Washington) Evening Star , July 23, 1971
By Mary McGrory, Star Staff Writer
AP PHOTO: JOHN KERRY(snip)
Four heckling women infiltrated a press conference called by John Kerry yesterday to accuse the President of using the prisoners of war for political purposes.
In voices shaking with nerves and rage, the ladies in the back of the room, all relatives of POW's, accused Kerry of using the prisoners for his own political purposes.
"What are you running for now, Mr. Kerry?" screamed one of the disrupters.
Other POW kin who had gathered with Kerry to demand action on the Viet Cong's recent prisoner-release proposal were the targets of some of the ladies' taunts: "You're stupid, Kerry is using you to run for office." The four noisily stomped out. They were under the escort of a representative of the Veterans of Foreign Wars, which regards the stylish and eloquent Kerry, spokesman for the Vietnam Veterans Against the War, as public enemy number one.
Source:
FBI FOIA - VVAW CD1, 100-HQ-448092
File: Sub A Section 01.pdf, p. 73
Yes, I believe that is the one. Great research.