The "Hollywood Head" murder is featured on Monday's People Magazine Investigates episode

From the grisly crime scene to the shocking motive, the murder of Hervey Medellin has all the makings of a Hollywood screenplay.

Medellin’s murder is the focus of the upcoming People Magazine Investigates episode “Hollywood Horror Story,” which airs Monday night at 10 p.m. ET on Investigation Discovery.

Ahead of that airing, PEOPLE Senior Editor Alicia Dennis sat down on Friday’s People Now to preview the episode and discuss some key features of the case.

Medellin’s Remains Were Found in an Iconic Spot

In January 2012, a dog walker and her mother discovered a bag containing a severed headjust off a wooded trail near the famed “Hollywood” sign. They first thought the head belonged to a mannequin, but soon learned that the head belonged to the 66-year old Medellin.

His feet and hands were located about 50 yards from the head. It wasn’t until years later that hunks of Medellin’s flesh were retrieved from deep inside the bat cave. His torso was never found.

The quarry in which the cave was found had once appeared as the entrance of the Batcave in the 60’s “Batman” TV series.

• For more on the case of the Hollywood Head, watch “Hollywood Horror Story” on our 10-part true crime show, People Magazine Investigates, airing Monday nights at 10 p.m. ET on Investigation Discovery

Image #: 27981577 Gabriel Campos-Martinez, 38, is seen in an undated photo released by the Bexar County Sheriff's Office in San Antonio, Texas.
Gabriel Campos-Martinez
| Credit: Bexar County Sheriff's Office/Reuters/Landov

Police Investigated Several Possible Suspects

Authorities seemingly left no stone unturned in their investigation. In an email to friends, Medellin’s boyfriend alleged that he had gone to Tijuana and never returned. That fact that Harvey worked for the cartels as a concierge in the 1990s prompted authorities to consider that Mexican drug cartels were involved.

They also looked into Luka Magnotta, a Canadian porn actor convicted last December of dismembering a Chinese exchange student and sending some of his body parts to members of the Canadian Parliament.

Neither of these leads panned out, however, and police soon began searching closer to home for the killer.

WATCH: “Hollywood Horror Story” on People Magazine Investigates

The Motive: Love Gone Wrong

While authorities investigated several possible motives, they eventually zeroed in on Medellin’s boyfriend and roommate, Gabriel Campos-Martinez. But there was another potential suspect: William Ladewig, the man Campos-Martinez had left so he could be with Medellin.

Authorities said Ladewig hadn’t handled the breakup well, and began intimidating the new couple. His behavior became so threatening that Campos-Martinez sought a restraining order against Ladewig.

Police eventually determined that Ladewig had no involvement in Medellin’s killing and arrested Campos-Martinez in 2014.

Campos-Martinez was convicted of the murder in 2015, and sentenced to 25 years to life in prison.

To find out more about this case, watch the “Hollywood Horror Story” episode of People Magazine Investigates this Monday (10 p.m. ET) on Investigation Discovery.