It is a terrifying sound nobody wants to hear, but it happened early Wednesday in northwest San Antonio.

A young mother told San Antonio police that she woke up to a deafening blast and found her 3-year-old son with a gunshot wound.

It happened in the Northwest Trails community on Loop 1604 near Culebra.

Police say that the call for help came around 8 a.m. when a frantic mother said her young son found her boyfriend's gun while she slept.

"A 3-year-old child accidentally discharged a weapon," Officer Carlos Ortiz said.

The mother, whose name has not been released, told police that the gun was in a holster, hanging on the bed frame.

"The child was shot in the abdomen area,” Officer Ortiz described.

With the gun owner at work, police say that they will be looking at every element of what seems to be a tragic accident.

"It's imperative that we do a good job and do a good investigation into the matter,” Officer Ortiz said.

Police say that there was a second child in the house at the time of the shooting. They said that child is okay.

The injury to the child left first responders in a somber mood.

Officer Ortiz says that gun safety is a very important issue to everyone in the law enforcement community.

"I'm a perfect example. I have a 3-year-old and I have guns in my home. I just have them out of reach from my 3-year-old and, at the same time, I tend to have them locked up or secure in a place where young children can't reach them," Officer Ortiz said.

Residents in the Northwest Trails community declined to speak on the record, but privately, the neighbors said that the quiet community of mostly retirees is united in their hope for a good outcome.

With regard to a condition update, the hospital needs a parent's approval to release that information, and so far, the hospital has released no new information.

Police said that the child was taken to University Hospital in critical condition.

The investigation continues.