Sometimes, it’s the forbidden stories, the ones people are afraid to tell in full, the ones that emerge only in fragments, that reveal the truth about a place.

This is such a story.

It’s being told now not because the complete truth is known, but because the story nags at those familiar with its outlines, and because it says as much about Iraq’s progress as it does about Iraq’s resistance to change.

This much is known:

A young woman imprisoned in Tikrit, north of Baghdad, sent a letter to her brother last summer, appealing for help. The woman, named Dalal, wrote that she was pregnant after being raped by prison guards.

The brother asked to visit her. Guards obliged. The brother walked into her cell, drew a gun and shot his visibly pregnant sister dead.

His goal: to spare his family the taint of a pregnancy out of wedlock, a disgrace in Iraq often averted through so-called honor killings of women by their relatives.

For prison guards, the killing was also a relief.

“They believed that her death would end the case,” said a lab worker at Baghdad’s central morgue, where the victim’s body — still carrying the 5-month-old fetus — was sent.

The case might have ended there were it not for the morgue employee, who was determined to see those responsible held to account.

At the employee’s insistence, lab workers using freshly acquired DNA-testing equipment drew a sample from the fetus. The prison guards were ordered to submit DNA samples and did so, apparently unaware of the sophistication of the morgue equipment and the people trained to use it.

“They thought we were incapable of figuring it out,” said the morgue employee.

The DNA results showed that the father of the unborn baby was a police lieutenant colonel who reportedly supervised guards at the prison.

In another society, the scientific evidence would have led to arrests and prosecution. But this being Iraq, the power wielded by men in uniform and the belief that a raped woman is better off dead combined to cloud the truth.

Months passed after word leaked of the killing on a sweltering summer day. Just as it nagged at the morgue worker, it nagged at us. But how to tell a story that nobody wants told? Everyone had different, usually conflicting, versions of what had happened.

Only the morgue worker’s story remained the same, repeated in phone calls and e-mails as summer turned to fall and then winter.

Then, it was time for one of us to leave Iraq. A colleague asked what the reporter’s final story would be. There must be one after so long in the country, he insisted.

“Isn’t there a story that got away?” he asked.

It became clear that this was it, even if we still didn’t know the truth.

About the only thing anyone agrees on is that a young woman was murdered, and that her last days were spent pregnant and worrying about what would happen if she were released into a society that would condemn her for it.

According to a judge in the Tikrit court, the lieutenant colonel implicated by DNA and a police captain also accused in the case were arrested on rape charges but then released for lack of evidence. The judge said a third defendant, a police lieutenant, remained in custody. (It is not uncommon in Iraq for police officers to serve as prison guards and supervisors.)

Another Tikrit court official said the lieutenant colonel and captain remained in custody but were transferred from Tikrit to Baghdad. Col. Hatem Thabit, spokesman for the police in Salahuddin province, where the crime was committed, concurred with this account.

Yet other accounts say the matter was settled through tribal justice. The clan of the accused lieutenant colonel paid the woman’s family to drop charges, said some people in the area who are familiar with the case but fearful of discussing it openly.

The morgue worker said those involved in the lab testing understood that all three of the police officers were freed.

“I heard the dispute was solved by a tribal ransom,” the employee said.

“The issue bothers me a lot. I’m doing my job, and the bad guys are getting back on the street.”

There are conflicting reports on the brother’s status. Some say he was jailed for killing his sister. Others say he was freed as part of the tribal deal.

As for the slain woman, several accounts say she was in prison not because she was a convicted or accused criminal, but because police wanted to question her brother about something. They thought he would turn himself in to free Dalal. Nobody has been able to explain why police wanted to talk to the brother.

The prison where she was held houses mainly men. There is a small section for female inmates, usually no more than a few at a time. A female guard is supposed to watch over them. No one could explain how the lieutenant colonel was able to do what he did.

Nor could anyone say how Dalal’s brother got into her cell with a loaded gun.

“He was supposed to be searched,” said Thabit, the police spokesman. “Where he got the weapon, we don’t know.”

In Iraq, violence against women is a festering but rarely addressed problem. There are no readily available statistics on “honor” killings. The number of rapes reported to police averages five to 10 per month for the entire country, said an official at Baghdad’s central morgue, who released the first details of the Tikrit case last summer.

“The actual number of rapes is actually more than we know. There are so many rapes in the prisons, for example,” he added before going on to cite the Tikrit case to an Iraqi working for The Times. Realizing he was discussing a case not intended for public consumption, the official urged the reporter not to translate the facts for his English-speaking colleague.

But minutes later, another morgue official and then the lab worker confirmed the case. All asked not to be identified for fear of losing their jobs.

Other workers interviewed during a daylong visit to the morgue, where rape victims are examined, said they had detected an increase in violent crimes against women since the 2003 U.S.-led invasion ushered in a religious conservatism and brought social and economic upheaval.

Most are honor killings, said one morgue employee, who a day earlier had received the body of a pregnant woman with her throat slit.

Human rights advocates say many of these homicides are made to look like honor killings to gain leniency for the perpetrators.

“It’s a lot worse now,” said Ibtisam Hamody Azzawi, a former engineer who runs a small aid organization for abused women from her home in Baghdad.

“Our society witnessed so much war, and this is reflected in the domestic abuse situation.

“Everything is violence. Even the kids love war,” said Azzawi, whose husband, a university dean, was killed by extremists in 2007.

Much of her time is spent answering knocks on her door or phone calls from women looking for an escape from abusive homes. People find her by word of mouth. She does not tell her neighbors what she does, lest extremists attack her or one of her daughters.

Iraq has no shelters for battered or threatened women, and the war has splintered and displaced families who might have taken in female relatives. Amid the turmoil, homicide has become an easy out for husbands wanting to end their marriages, Azzawi said. It’s cheaper than divorce.

“Women get killed, but often it is reported that they are missing,” she said. “It’s all part of the chaos. Some husbands kill their wives and say maybe she was kidnapped, maybe she died in a bombing.

“A husband and wife will have domestic problems. All of a sudden, the wife will disappear.”

At the women’s prison in Tikrit, Saturday is visiting day. On a summer Saturday, a brother came to see his sister, her stomach swelling with her unborn child.

She trusted him.