A 27-year-old Iraq War veteran who suffered from Post Traumatic Stress Disorder killed his 11-year-old sister, before killing himself, according to Gilroy police.

Police said they have not been able to locate the man’s mother, and fear he may have also killed or seriously wounded her.

“It’s horrible,” said Gilroy Police Sgt. Chad Gallacinao. “We have no idea where the mom is.”

Gilroy police said they rushed to an apartment complex at 9005 Kern Avenue about 9 p.m. Wednesday, after a roommate in the home reported that something might be wrong.

When police arrived, they found the 11-year-old girl, whom the Gilroy Dispatch identified as a South Valley Middle School Student, dead, with a bullet in her head. Her brother, Abel Gutierrez, was also dead, from a self-inflicted gunshot wound, according to police. He served in the Army and had recently returned from serving in Iraq, police said.

Gallacinao said at least two firearms were used in the murder-suicide. He would not disclose whether Gutierrez left a note. And he would not disclose who else is in the Gutierrez family, other than Abel’s mother, Martha Gutierrez, 52, who may be in need of serious medical attention.

“There was forensic evidence located at the scene to suggest that Martha Gutierrez is critically injured or deceased,” a police statement read.

Kristell Gutierrez, who said she was a niece of Abel, said her uncle would say he wanted to kill himself “all the time,” and would ask family members if that would hurt them.

A Veterans Administration spokeswoman in Palo Alto said Gutierrez received treatment for Post Traumatic Stress Syndrome at a VA facility in Puget Sound, Washington. Officials at that Puget Sound facility could not be reached for comment.

One neighbor of the Gutierrez family said she was so worried about the strange antics of Abel Gutierrez that she would not allow her daughter to play upstairs near the Gutierrez’s unit.

Alissa Fernandez, a downstairs neighbor, said the veteran “was just weird, the way he would act.”:

Fernandez said just two weeks ago, Martha Gutierrez apparently went to the apartment manager, saying she was “scared of her son.”

Her son had thrown a plastic jug of Tide at her, Fernandez said. The container broke in half and the liquid detergent leaked down the stairs outside the apartment. Fernandez said she talked to Martha and her daughter Lucero while they were cleaning the detergent up. That’s when the son yelled from the window, “Are you done?” — all like he was being controlling, according to Fernandez. The mom didn’t say anything, but Lucero said, “Yeah, almost.”

Fernandez said 11-year-old Lucero was “so innocent.” She would play with Fernandez’s six-year-old daughter almost every day.

Kristell Gutierrez said she knew her uncle was “very mean” to his mother and blamed her for the fact his father left the family.

Gilroy police visited the home at least one other time recently. Gallacinao said police were called to the apartment complex on Feb. 29, because his family members suspected that he suffered from PTSD.

But Gallacinao said Gutierrez did not seem dangerous and “did not meet the criteria” to bring in on a psychiatric hold. Instead, Gallacinao said that police began working with the family and the Office of Veterans Affairs in Palo Alto to help Gutierrez get services.

Anyone with information regarding Martha Gutierrez’s whereabouts or this case to contact Detective Michael Bolton at 408-846-0350.

Check back for more on this developing story.

Contact Lisa Fernandez at 408-920-5002. Follow her at Twitter.com/ljfernandez.