Lyford police search the streets.
Volunteer firefighters use brush trucks to navigate more difficult terrain.
A Border Patrol K9 is called in to assist.
Despite the multi-agency efforts, there are no signs of missing 41-year-old Maria Guadalupe Hernandez.
Her sister, Norma Hernandez, recalls where she's seen last.
"Wednesday afternoon at 5:30, she went out walking, her regular walk, and she never came back," she said.
Norma says it's unusual for her sister to be gone for this long.
She hasn't shown up at her job where she works in food service at a Harlingen hospital for the past 2 days, according to the missing woman's family.
Maria's cell phone, car keys and purse are all left behind at her home located East of Expressway 77 along Broadway where the search for her takes place.
Lyford police are concentrating their efforts in the wooded areas around the city.
That's because of previous threats family member say she made on her own life.
"We have to look at the possibility that she wanted to commit harm to herself," Lyford Police Chief Paul Campbell said. "Maybe she could have been abducted. We try to keep an open mind on things that she is okay."
The chief says his department recovered receipts in Maria's purse that indicate that she purchased a gun and ammo the day before her disappearance.
Other details family members shared with police about Maria's past trouble the chief.
"That she has been struggling with a couple of mental illnesses and that's a major concern for us," he said.
Maria is described as 5 feet, 6 inches tall, weighing 130 pounds with black hair and brown eyes.
She's last seen wearing a blue shirt and black pants.
Norma refuses to give up hope that her sister is still alive.
"We just want her to come home," she said.
The family plans to do a search of their own on Saturday morning at 8am.
Anyone with information should contact Lyford Police at (956) 793-4198.
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