(NBC News) — Friday on “Dateline,” in the summer of 2018, the Webb County Sheriff’s Department begins investigating a string of deadly shootings targeting women in the border city of Laredo, Texas.

When the lead investigator calls in reinforcements from other law enforcement agencies to help solve the case, an unexpected suspect comes to light. 

Here is a preview of Josh Mankiewicz’s report:

Investigators in Laredo, Texas were working the murder of Melissa Ramirez — found dead on the side of a desolate road.

Sheriff’s captain Federico Calderon knew he’d need help, so he called in the Texas Rangers, the Department of Public Safety and the U.S. Border Patrol.

FEDERICO CALDERON: We resorted to, uh, what cops do best, and that’s being nosy and talking to people.

That meant scouring the corners of San Bernardo.

JOSH MANKIEWICZ: One of the names you hear, when you’re building a profile of who Melissa was, is Claudine Luera.

FEDERICO CALDERON: Correct. They worked in the same area. They, they were acquainted. They knew each other.

JOSH MANKIEWICZ: Both prostitutes, both on drugs?

FEDERICO CALDERON: Correct.

Investigators thought Claudine might know who it was that Melissa so feared — except she was nowhere to be found.

They put out the word among other law enforcement agencies, but Claudine didn’t turn up.

JOSH MANKIEWICZ: Possible that she heard you guys were looking for her and was keeping her head down?

FEDERICO CALDERON: That is a possibility, for sure.

Ten days after Melissa’s murder, they finally found Claudine Luera. She wasn’t talking.

JOSH MANKIEWICZ: She’s been shot.

FEDERICO CALDERON: She’s been shot.

It was about two miles from where Melissa’s body was found, also by the side of the road. Nearby, the same 40-caliber federal ammunition.

Claudine was taken to a hospital. She did not survive.

FEDERICO CALDERON: It’s starting to smell like it’s the same guy, and we have a strong inclination after processing that crime scene that we’re probably dealing with the same person.

JOSH MANKIEWICZ: Someone’s killing prostitutes.

FEDERICO CALDERON: Someone’s killing prostitutes with a 40-caliber handgun.

Watch “Dateline: The Streets of Laredo” Friday on NBC4 at 10 p.m.