A teen girl in Texas is dead after being shot 22 times while walking her dog on Tuesday evening, despite frantic efforts by her parents to save her, KPRC-TV reports.

Family members of the 15-year-old girl, Diamond Alvarez, are now grieving and searching for answers.

“Whoever shot this girl 22 times in the back, they are cowards,” Alvarez’s stepfather, Tito Moczygemba, told the television station.

Police were called to the shooting scene in southwest Houston around 9:30 p.m. When officers arrived, they found Alvarez’s body with numerous gunshot wounds. She was later pronounced dead.

Authorities say that at the time of the shooting, Alvarez was out walking the family’s dog, named Peanut. When Alvarez did not return home, family members became concerned and went outside, where they found the dog but not Alvarez.

The family then went looking for her in the neighborhood and found her in a field. Anna Machado, Alvarez’s mother, told KPRC-TV that she tried to save her daughter.

“I tried CPR. I couldn’t bring her back,” Machado told the television station. “I tried so hard to keep her alive.”

Multiple gunshots had been heard in the neighborhood where Alvarez’s body was found, according to the Houston Chronicle.

Alvarez was reportedly a sophomore at Madison High School, where she was an honor student. She had planned to attend cosmetology school.

Investigators say a dark vehicle may have been involved in the shooting, KPRC-TV reports. Police are checking for possible surveillance footage from the area and want to speak with witnesses.

To report information about the case, call the Houston Police Department at 713-308-3600 or call Crime Stoppers at 713-222-TIPS.

For the latest true crime and justice news, subscribe to the ‘Crime Stories with Nancy Grace’ podcast. Listen to the latest episode: