A 15-year-old girl was fatally shot in the back while walking her family dog near her Houston home.

Diamond Alvarez was discovered lying in a field after she was struck 22 times in the back around 9:30 p.m. on Tuesday night.

The family say Alvarez had previously argued with her boyfriend and had agreed to meet with him at the site where she was killed.

No arrests have yet been made. 

Her family told Houston NBC affiliate

Moments later they heard scratching at the door and found the animal, with his leash and harness covered in blood, had run back to the home. 

'When they saw Peanut by himself, they knew something was wrong,' said Ashley Machado, the teen girl's older sister. 

They quickly ran to find her.

Alvarez's mother Anna Machado said her youngest son found Alvarez in a field, by  the side of a road on 15400 Park Manor near Markwood Lane.

She had been shot 22 times but she was still alive. Her mother desperately tried CPR but she died at the scene.

'My son found her. I tried CPR, and I couldn't bring her back. I tried so hard to keep her alive. I couldn't,' Anna told local Fox affiliate 

The Houston Police Department said neighborhood residents claimed to have heard multiple shots and that a dark-colored car reportedly speed off from the site of the attack, traveling north on Markwood Lane.

'Whoever shot this girl 22 times in the back, they are cowards,' said Anna's partner Moczygenba.

Alvarez was a sophomore and made the honor roll at Madison High School.

She was described as a straight-A student, who played volleyball and basketball, and was looking forward to a career in cosmetology. 

A makeshift memorial has been set up at the spot where Alvarez was found. 

'I mean, the person that did that to her was very cold hearted,' Jovanna Martinez, a close family friend and neighbor, told

Diamond Alvarez was killed near her home in Houston on Tuesday night while walker her dog