Texas cops are looking for a heartless gunman who shot and killed a diabetic teenager’s service dog.

The adorable 4-year-old golden retriever, named Journey, was found lying motionless outside the Westmoreland family’s home in Quinlan on Sunday morning and died at the veterinarian’s from his wounds, the family said.

“It’s been awful for us all,” Tina Westmoreland told ABC News on Tuesday. “He was amazing.”

The fourth-grade math teacher was able to afford the dog for her daughter Hannah four years ago thanks to her town’s residents, who raised $10,000 for the service animal, trained to detect high or low levels of blood sugar.

When the 15-year-old’s blood sugar was reaching dangerous levels, the dog “would poke her with his nose on her leg. He got in front of her, made sure she stopped and listened to him,” Westmoreland said.

Now that he’s gone, Westmoreland will have to check her daughter’s blood sugar at least twice each night. Hannah was diagnosed with diabetes in 2012.

“It scares me to death to try to replace Journey,” she told the Dallas Morning News. “For now, I’ll be more proactive in checking her sugars.”

The Hunt County Sheriff’s Office is investigating the shooting.

A family member has also set up a Facebook page and a GoFundMe campaign, Justice4Journey, to raise awareness about the shooting.

“Not only was Journey Hannah’s lifesaver he was part of the family and all loved him dearly,” a post on the page reads.