Though it's been a year since the slaying of fitness instructor Terri "Missy" Bevers at a Midlothian church, police say they are determined to keep the case from going cold.

Missy Bevers ((Facebook))

Investigators have spent thousands of hours poring over hundreds of tips, but there have been no arrests in the slaying.

A full-time investigator remains assigned to the case, and police are still vetting a few persons of interest. Police have not named a suspect, Assistant Police Chief Kevin Johnson said.

"Nothing too new except the passage of time," he said.

The Red Oak mother of three was attacked shortly after 4 a.m. on April 18, 2016, at Creekside Church of Christ, where she was setting up for an early-morning Camp Gladiator fitness class. Participants in the program discovered her body.

Immediately after her slaying, police released surveillance footage of a person of unknown gender clad in SWAT-type gear swinging what looks like a hammer while walking through the church with a distinctive gait.

Bevers, 45, had puncture wounds to her head and chest, according to a search warrant obtained by KXAS-TV (NBC5). Nothing was taken from the church.

Police communicate regularly with the family and continue to work as needed with the FBI, Johnson said.

"I think there's still a lot of concern in the community here," Johnson said. "Certainly nobody in our building has moved on or forgotten. I really do think the guys working on this case are as diligent now as they were then, and as passionate about finding justice for Missy."

In the first month, dozens of officers from Midlothian and outside agencies were working on the case. The first six weeks of the investigation alone cost more than $460,000 in payroll expenses, and the department spent thousands for just one forensics test, Johnson said.

By June, tips began to dwindle. As the case approached the six-month mark, detectives did more interviews and examined their work, searching for something to move the case along, he said.

Of the 1,300 tips they had received by that point, most led to dead ends.

Police said they would fully exploit any technology or resource available to find whoever is responsible for Bevers' death.

While it has been a frustrating case for the department, "our frustration doesn't compare at all to what the family's going through, and it's frustrating to not be able to give the family answers," Johnson said.

The department hasn't had an unsolved murder since the 1980s, when a body was dumped in a field off U.S. Highway 287. The few suspects police had died before the case could be proved, he said.

Bevers' friends and family still hope for a resolution and continue to honor her memory.

Renee Jones, a head trainer for Camp Gladiator, set up a Facebook event for a moment of silence at 5 a.m. Tuesday to remember Bevers. A year earlier at that time, Bevers would have been preparing to host her fitness class.

"You have sad moments, you have angry moments. You have moments where you're up here because you remember all the amazing things she did and said," Jones told WFAA-TV (Channel 8).

A screen shot from surveillance footage shows the suspect inside Creekside Church of Christ.

Her family declined to comment to KTVT-TV (Channel 11), but said they would be celebrating Bevers' life privately.

Police have reiterated that her family members, friends and co-workers are not suspects. There is still a $40,000 reward in the case.

"Missy was a beloved mother, wife, daughter, and sister. She, her family, and our community deserve our best effort," police said in a prepared statement. "Since the beginning, finding justice for Missy has been our number one priority. We will do that by following the evidence wherever it may lead us."

Police urged community members to come forward with tips, and said they believe someone has been withholding that "vital piece of information" that could help solve the case.

"As long as there's anything to be done, we'll leave this case open," Johnson said.

Anyone with information about the suspect is asked to call Midlothian police at 972-775-7624 or Ellis County Crime Stoppers at 972-937-7297.