It was a small way of offering a big “thank you” to the Roswell police department. The family of a teenager murdered behind a Publix grocery store treated officers to lunch Thursday, publicly thanking the detectives that solved the case.

"Our family could not be more grateful,” Rachael Henderson told the officers, Channel 2 Action News reported. “We know you worked around the clock without sleep, without spending time with your families in order to make an arrest and help our family and the Davis family."

Henderson’s older sister, Natalie, and her friend, Carter Davis, were killed during early-morning hours Aug. 1. The 17-year-olds would have started their senior year of high school.

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The deaths shocked the Roswell community. But within 48 hours, police announced an arrest in the case. Jeffrey Hazelwood, 20, had an extensive history of mental illness and later described his actions to detectives, though never offered a motive.

In May, Hazelwood pleaded guilty but mentally ill to murder charges and was sentenced to life in prison without parole. He spoke very little, but through his attorney, Hazelwood said he was remorseful.He spoke very little, but through his attorney, Hazelwood said he was remorseful.

Both Natalie and Carter’s mothers spoke in court prior to the sentencing, with each reading emotional statements words about the outgoing, caring teens. On Thursday, it was Rachael Henderson that spoke on behalf of her family.

“You were honest and candid throughout the process and more than anything you truly care about Natalie and our family,” Rachael said. “We consider you family."

Roswell police Chief Rusty Grant said the case impacted everyone in his department.

"This Is a very rare situation where we actually have a victim's family, come forward many months after the investigation was complete, and offer to do something for the department,” Grant said.

Jeffrey Hazelwood, 20, pleaded guilty but mentally ill in the August 2016 killings.