A woman charged with bludgeoning two of her sons to death with rocks and critically injuring a third child may not understand the capital murder and aggravated assault charges against her, her attorney said in court Monday.

Two days after Deanna LaJune Laney, 38, called 911 to report killing two of her sons, the petite woman appeared in court, wide-eyed and nodding responsively when District Court Judge Cynthia Kent asked her if she understood her rights.

Laney's newly appointed attorney, F.R. "Buck" Files, questioned Laney's understanding of the situation.

"I'm not sure if she can truthfully say she understands what is going on," Files told the judge.

Laney is accused of killing Joshua Laney, 8, and Luke Laney, 6, and injuring their 14-month-old brother, Aaron. The toddler remained in critical condition Monday at a Dallas hospital.

In a call to emergency workers early Saturday, Laney reported that she had just "bashed their heads in with a rock," Sheriff J.B. Smith said.

When they arrived at the home, sheriff's deputies found Joshua and Luke dead in the yard wearing only their underwear, large rocks on top of their bodies. Aaron was found in his crib with a pillow over his face, alive but bleeding.

The sheriff said Laney acted erratically Sunday during interviews with investigators.

"Sometimes she is incoherent, sometimes she's in a fetal position and sobbing. Sometimes she's singing spiritual hymns or muttering about God and sometimes she has a flatliner [poker] face and not saying a thing during interviews," Smith said.

At a news conference after the hearing, District Attorney Jack Skeen said he knew of no evidence to suggest that Laney suffers from mental health problems or was confused about her circumstances.

"I don't know if the term incoherent would apply," he said.

The district attorney said it is too early to decide whether to seek the death penalty.

The boys' deaths were announced Sunday to more than 200 members of the First Assembly of God Church, where Laney sang in the choir and her brother-in-law, Gary Bell, is the pastor.

"We all believe as a family that this wasn't our Dee that did this to her children," Bell said.

Another Texas woman, Andrea Yates of Houston, confessed to drowning her five children in a bathtub in June 2001 and was convicted of murder. The jury rejected defense pleas that Yates was innocent by reason of insanity. She was sentenced to life in prison and is not eligible for parole until 2041.