Elia Martinez-Bermudez was trying to get out of the alleged abusive relationship. She talked to Irving Police Department counselors. She filed for a temporary protective order against her ex-boyfriend.

But her attempts appear to have come too late: Police said her estranged boyfriend Hector Medina fatally shot the couple's two young children before turning the gun on himself the day before a Dallas County judge was to sign the temporary order against the 27-year-old man.

Now law enforcement and criminal justice officials fear that what happened to Ms. Martinez-Bermudez will make victims in abusive relationships stay in violent couplings and shy away from help.

"I don't want for victims to think that protective orders are worthless, and I don't want them to think they are bulletproof vests," said Cindy Dyer, co-chief of the Dallas County district attorney's office's family violence division.

According to an affidavit Ms. Martinez-Bermudez filed in Dallas County on Friday, she left Mr. Medina last week after what she described as a five-year relationship riddled with rape, physical abuse and threats against her and the children if she ever left.

Ms. Martinez-Bermudez could not be reached for comment.

On Sunday, Irving police responded to a home in the 3100 block of Roanoke Drive that the couple shared with another family. Mr. Medina was outside, suffering from self-inflicted gunshot wounds, police said.

Officers found 3-year-old Javier and 8-month-old Diana inside the home. Police said Mr. Medina had shot the two children, who were taken to Children's Medical Center Dallas, where they died.

On Tuesday, Irving police served a capital murder arrest warrant on Mr. Medina at Parkland Memorial Hospital, where he remained in critical condition.

Early last week, police responded to the same home on a domestic disturbance call. Police spokesman David Tull said no offense report was made because no crime had been committed. Ms. Martinez-Bermudez's affidavit indicates Mr. Medina was destroying some of her property.

"It's not against the law to tear up your own stuff," Officer Tull said. "Apparently in the case of the call on this one, she wasn't forthcoming of any information about any offense and there was nothing visible."

In Ms. Martinez-Bermudez's affidavit, she said that Mr. Medina assaulted her the next day for refusing to have sex with him. She also said she did not call police on that day because she believed Mr. Medina when he said officers would not believe her story.

Officer Tull said that police have reviewed last week's incident at the home but that hindsight adds a layer of understanding that didn't exist initially.

"It's a cycle that never ends," Officer Tull said of abusive relationships. "What they've seen over time is it gets worse and worse. The information we had didn't indicate something of this extreme nature coming this quick."

Officer Tull said that although officers did not file an offense report, they provided Ms. Martinez-Bermudez with phone numbers and lists of steps to take if she was trying to get out of an abusive situation.

"My understanding is that she did go to our counseling unit," Officer Tull said.

But according to officials, she didn't want to file a police report against Mr. Medina. Instead, she went to the Dallas County district attorney's office and filed for the protective order.

Ms. Dyer said her office offers people various options in protecting themselves as they try to get out of abusive relationships. She said the different orders they can request from a judge depend on the individual case.

But she said her office does not require police reports, medical records, an attorney to represent the victim or fees. She said her office tries to help victims in the way that is safest in their circumstances. Making the abuser even angrier, though, is always a concern.

"We should not sit back and ever say, 'She should have done this, she should have done that,' " Ms. Dyer said. "They are making the best decision they can knowing what they know. We cannot be judgmental because we don't know him as well as she does."

She said she doesn't know if Mr. Medina was aware that his ex-girlfriend had filed for a temporary order. But she said the time period between the filing for an order and a hearing on the motion is held is sometimes the most dangerous for people in abusive relationships.

"Does that mean you shouldn't leave?" Ms. Dyer said. "No. That means when you do leave, you need to be smart and you need to be prepared. You need to think about the safest and best way to leave."

Ms. Dyer said that shelters are often the best places for abuse victims to go after leaving a relationship, even if the victim has money, nearby relatives or a lot of resources. Still, she said the death of Ms. Martinez-Bermudez's children is a rare and extreme case.

Officer Tull said it's one that will probably stay with his department for a while.

"We'll beat ourselves up over this one, but when you really go back and slice and dice it, I don't see where we could have done anything else," he said.

He said that abuse victims often don't tell anyone about the dynamics of the relationship, which can usually contain periods of happiness and stability.

"If you're in a situation you're not happy with, or things are going wrong, it won't get better unless you get out of it," Officer Tull said. "The only way to get out is to make a move to get out of it. Talk to other people because you're not in it alone. Other people have been it before."