LAWRENCEVILLE, Ga. >> A woman charged with killing four of her young children and her husband smiled and flashed a double thumbs up to news cameras during her first court appearance today in metro Atlanta before telling a judge she doesn’t want an attorney.

Also, an immigration official said the woman, who is from Mexico, entered the U.S. illegally.

Isabel Martinez, 33, appeared before Gwinnett County Magistrate Court Judge Michael Thorpe a day after police said she stabbed the five to death and seriously injured another child at her home. The surviving 9-year-old girl remained hospitalized with serious injuries.

Before the hearing began, Martinez sat with other inmates and posed for cameras — smiling, giving the thumbs up, putting her hands in a prayer position and spreading her arms out wide.

As Thorpe listed the charges — five counts of malice murder, five counts of murder and six counts of aggravated assault — Martinez smiled, shook her head “no” and wagged her finger at him.

“Ma’am, I’m going to caution you to cut out the display for the cameras,” he said. “It’s really not a good idea, probably not to your benefit.”

When Thorpe said she had a right to an attorney, she replied through a Spanish-language interpreter that she doesn’t want one. She later added that her attorney will always be the people “that we’re fighting for” and her faith.

“You are the hope of the world, each one of you,” she said in Spanish, appearing to address the news cameras. “It doesn’t matter what color you are because God loves us all.”

Thorpe advised Martinez to hire a lawyer or allow one to be appointed.

Meanwhile, U.S. Immigration and Customs Enforcement spokesman Bryan Cox said in an email today that Martinez — whom he identified as Maria Isabel Garduno-Martinez — is from Mexico and entered the U.S. illegally. This is her first encounter with immigration authorities, and it’s not clear how long she has been in the U.S., Cox said.

Local officials called the killings “horrendous.”

“What prompts a person to take the life of such innocent children and her spouse is something we may never understand,” Gwinnett County police said in a statement.

Psychologists and others who study cases of mothers killing their children say it’s not as uncommon as people might believe. But media coverage often focuses on dramatic cases, such as Andrea Yates, who was found not guilty by reason of insanity for the 2001 drowning deaths of her five children in her suburban Houston home.

Other cases get less attention, as when a woman kills a newborn or in children’s deaths blamed on neglect, said Cheryl Meyer, a psychology professor at Wright State University in Ohio and co-author of two books on mothers who have killed children based on about 1,000 cases during the 1990s.

In cases when mothers kill intentionally, Meyer said there is often another influence, such as mental health issues or the loss of a close loved one.

“We like to classify these women as pariahs, that they aren’t at all like us,” Meyer said. “I found that was not the case.”

Some neighbors in the small, largely Hispanic neighborhood in Loganville, about 30 miles (48 kilometers) east of Atlanta, said the Spanish-speaking family had moved to the community recently. The children seemed happy playing with other neighborhood kids, they said.

Victoria Nievs said Martinez had recently suffered the death of her father.

Police believe the 911 call reporting the stabbings was made by Martinez. Gwinnett County Police Cpl. Michele Pihera said the caller was speaking Spanish, which initially made it difficult for 911 operators to communicate with her.

The four children killed were identified as Isabela Martinez, 10; Dacota Romero, 7; Dillan Romero, 4; and Axel Romero, 2. Their slain father was Martin Romero, 33, Pihera said.

Associated Press writers Jonathan Landrum Jr. and Jeff Martin in Atlanta contributed to this report.