Patricia Kutteles, who helped repeal the military’s “don’t ask, don’t tell” policy with emotional testimony about the murder of her son, a soldier who was rumored to be gay, died Nov. 14 at a hospice center in Kansas City, Mo. She was 67.

The cause was cancer and other ailments, said her husband, Wally Kutteles.

Mrs. Kutteles was drinking coffee on the July morning in 1999 when she received a phone call from Fort Campbell, Ky., where her 21-year-old son, Pfc. Barry Winchell, was serving as an Army infantryman. He had won accolades for his marksmanship and aspired to be a helicopter pilot.

In that phone call, Mrs. Kutteles learned that her son had been attacked. The details would later trickle out: Winchell was sleeping in his barracks when a fellow soldier, Pvt. Calvin Glover, 18, set upon him with a baseball bat. A witness would later testify that the left side of Winchell’s head was broken “like an egg shell.” He died the day after the attack.

Only in the aftermath of her son’s death did Mrs. Kutteles learn that, for months, Winchell had been the target of homophobic bullying by fellow soldiers. Word had gotten around that he was dating a preoperative transgender woman, and rumors swirled that Winchell was gay.

“Pretty much everybody in the company called him derogatory names,” Winchell’s section leader said in testimony. “ . . . A lot of times, he was walking around, down in the dumps.”

Explaining why he took no steps to stop the harassment, the sergeant said, “Everybody was having fun.”

Winchell was in a devastating bind: Under the “don’t ask, don’t tell” policy signed by President Bill Clinton in 1993, the Army was not permitted to inquire about Winchell’s sexuality, nor was he permitted to reveal it, if he was gay. If he complained about the harassment, he risked inflaming suspicions.

Mrs. Kutteles told reporters that if her son was gay, she had not known, but that his sexuality was beside the point. “The fact is, he was murdered, and he was on an Army base, where we thought he was safe,” she told NBC.

According to accounts of the incident, Winchell’s death was the culmination of days of hostilities, fueled by alcohol. Two days before the attack, Winchell had defeated Glover in a fistfight. Winchell’s roommate, Spec. Justin Fisher, 26, was accused of stoking Glover to get back at Winchell and with cleaning the bat after the attack.

Glover, who blamed the incident partly on alcohol, was court-martialed, convicted in December 1999 of premeditated murder and sentenced to life in prison with the possibility of parole. The next month, Fisher pleaded guilty to making false statements, obstruction of justice and providing alcohol to a minor. He was sentenced to 12½ years.

After the verdicts, Mrs. Kutteles began a campaign for what she regarded as more complete justice for her son, demanding to know why Army officials ignored excessive drinking on the base and why soldiers had been permitted to abuse her son. Most of all, she sought to repeal “Don’t ask, don’t tell.”

“We knew Barry could be deployed and come into harm’s way for our country. We never dreamed that he would be killed by labeling, prejudice and hatred at home,” Mrs. Kutteles and her husband said in a statement after Glover’s conviction. “ ‘Don’t ask, don’t tell, don’t pursue’ did not protect our son. It won’t protect anyone else’s child. This policy must end.”

Teaming with the Servicemembers Legal Defense Network, now known as OutServe-SLDN, Mrs. Kutteles spoke on Capitol Hill and to activists about her son’s death and about what she regarded as the corrosive effects of “don’t ask, don’t tell.”

The policy “says to other service members that gays in the military are second-class citizens, that they are not worthy of the respect dictated in the Army’s values,” she and her husband wrote in a CNN commentary. “Those who assert that the law serves to protect gays in the military are wrong — it corroborates the fears and bigotry of those who are anti-gay. Worse, it encourages those who are prone to violence to act on their rage.”

Amid pressure from Mrs. Kutteles, the Pentagon launched an investigation that found anti-gay harassment was widespread in the military. A subsequent, more targeted investigation by the Army inspector general found some harassment in Winchell’s unit but stopped short of determining there was a general atmosphere of homophobia at Fort Campbell and recommended that no senior officers be punished.

Mrs. Kutteles filed a wrongful death claim against the Army, accusing the military of failing to stop the harassment that led to Winchell’s death. The claim was denied, but Mrs. Kutteles did not desist in her efforts.

“Everything I’ve fought to find out — and I don’t care whether Barry was gay or not — leaves me worried about the safety of all the young men and women the Army is supposed to be looking after,” Mrs. Kutteles once told the New York Times. “I can’t bear to hear that Army recruiting song: ‘Be all that you can be in the Army.’ My son tried to be all that he could be, and he got murdered.”

In 2011, under President Obama, the “don’t ask, don’t tell” policy was repealed, allowing gays and lesbians to serve openly.

Matt Thorn, the executive director of OutServe-SLDN, said in an interview that Mrs. Kutteles’s story was “vital in that patchwork” of voices that helped overturn the policy.

“Pat had a unique story in the loss of her son,” he said, and “she found the resolve to go to Capitol Hill, go to the many members that had to be influenced . . . and have that conversation.”

Patricia Ann Slyker, the daughter of a Navy veteran, was born in Pearl Harbor, Hawaii, on March 30, 1949. She grew up in the Kansas City area and became a psychiatric nurse.

Her marriage to Grant Winchell ended in her divorce. Survivors include her husband of 34 years, Waldameer “Wally” Kutteles of Belton, Mo.; a son from her first marriage, Ian Winchell, also of Belton; a stepdaughter, Deborah Green of La Grande, Ore.; a brother; and several grandchildren. Another son from her first marriage, Sean Winchell, died in 2014.

As she spoke out for gay rights in the military, enduring the agony of reliving her son’s death, Mrs. Kutteles said that she found inspiration in a motto her son had learned from a drill sergeant in basic training.

“I hear him now, over and over, telling me, ‘Suck it up, Mom, and drive on,’ ” she told the Times. “Everything I’m doing is for him: Suck it up and drive on.”