A woman shot her two children before killing herself in Laredo on Monday night, hours after she released a man she'd held hostage in a Texas Department of Health and Human Services office, authorities said.

Laredo Police Department spokesman Joe Baeza said Timothy Grimmer, 10, and his sister Ramie Grimmer, 12, were flown to University Hospital in San Antonio with critical injuries after their mother, Rachelle Dianne Grimmer, 38, shot each of them once in the head around 11:50 p.m. Monday.

Rachelle Grimmer was pronounced dead at the scene, Baeza said.

“The children are very critical right now,” Baeza said Tuesday evening. “It didn't seem like they were being held against their will; they were just there with Mom.”

Grimmer, who recently moved to Laredo from Ohio, was upset because she was turned down for food stamps after applying in July, Baeza said. He said authorities believed her breakdown was “years in the making” after she had been denied benefits in various states.

Just before 5 p.m., the woman took out a handgun while speaking to two employees in a front office, police said. She demanded their supervisor, who arrived and told the woman he'd stay with her if she let his employees go.

She agreed, and the supervisor, Roberto Reyes, was taken hostage.

About 30 employees and clients were in the office at the time, Baeza said, and all but Reyes were able to leave.

“The supervisor was quite courageous, and did everything he could to preserve the life of his employees and to do everything he could to help the woman out,” Baeza said, adding that Reyes showed “uncommon valor in a life-or-death situation.”

Hostage negotiators spent the next couple of hours trying to persuade the woman to release the supervisor. Communication with the woman was intermittent, Baeza said, as the woman frequently hung up on negotiators.

Around 7:45 p.m., Reyes was released. The telephone communication continued, police said, but the woman hung up again around 11:45 p.m.

Officers then heard three gunshots, Baeza said.

SWAT team members who had surrounded the front of the building heard what sounded like children crying, Baeza said, and officers stormed the building, finding the three in the front office.

The children were unconscious when they were taken to a local hospital before being flown to San Antonio.

“Hopefully the children will pull through,” Baeza said.