How Police Foiled a Woman's Alleged Murder-for-Hire Plot to Kill Her Friend

— -- intro:Over the last three months, ABC News' "20/20" was given unprecedented access to an elaborate sting set up by an elite squad of Broward County Sheriff's deputies called the VIPER Unit.

The VIPER Unit designed a plan to stop an alleged murder plot against Maria Calderon by her former friend Jacqueline Luongo.

Luongo was charged with the murder of a woman she was living with for free in exchange for occasional driving and the attempted murder of Calderon. If convicted for both, she faces the death penalty. She has pleaded not guilty to both charges.

But Calderon and Luongo once had happier times together in Florida where the two friends both lived before Luongo allegedly tried to have Calderon killed.

Click through to go inside the VIPER Unit's sting to foil this alleged murder for hire plot.

quicklist:1text:Maria Calderon was close friends with Jaqueline Luongo, 44, of Ocala, Florida.

"I've known Jacqueline probably 10 plus some years," Jan Spear told "20/20." "She was a fun person."

Calderon was making ends meet working in a restaurant, but Luongo was having money trouble.media:28066823

quicklist:2text:Luongo made an arrangement with Pat Viveiros, a retiree living in south Florida. Viveiros agreed to let Luongo live with her in her Deerfield Beach, Florida, apartment in exchange for some occasional driving.

"[Viveiros was] very funny and loving," Viveiros' friend Michele Axton told "20/20." "If you were in a jam or whatever, she would be there for you."

Viveiros was living off her pension and an annuity from a life insurance policy. She would swing by a local bank to pick up her regular checks, and, police say, when Luongo figured this out, it was a tempting target.

"When you have no money, no apartment, no gas for your car, $50,000 in her opinion was worth more than Pat's life. So she exchanged Pat's life for $50,000," veteran Broward County Sheriff's Office homicide detective John Curcio told "20/20."media:28066931

quicklist:3text:On August 28, 2014, Viveiros disappeared.

"[She] hadn't been contacted on the phone for almost a week," Detective John Curcio told "20/20."

However, a woman matching Viveiros' description was seen a week later trying to cash Viveiros' most recent check.

Then, Luongo had a revealing conversation with her friend Maria Calderon.

"She [said] that Pat was dead," Calderon told "20/20." Calderon, not wanting any part of it, went straight to the police.

Police later arrived at Viveiros' apartment, and an officer found Viveiros' body inside a garment bag in a closet. The coroner determined that she died of asphyxiation.

"Her plan, my opinion: hide the victim's body as long as possible and keep on accessing withdrawals from the life insurance policy," Curcio said. "She's actually purchased a wig similar in color to the victim's hair... She's impersonating the person she killed, whose checks she's trying to cash at different establishments."media:28066978

quicklist:4text:Luongo was charged with murder and pleaded not guilty at her plea hearing. But while awaiting trial in a Broward County jail cell, police say Luongo began concocting a plan to have Calderon killed.

"She was actively soliciting within her cell – a group of people – ‘Does anyone have anyone who could help me remove a witness?'" Craig Brown, who runs the Broward County Sheriff's Office's VIPER Unit, told "20/20."

Brown said one of their jail house informants tipped them off that Luongo was plotting another homicide.

"Because in her twisted mind she thought that with no witness, there was going to be no case, and she can walk out," said Calderon.media:28067122

quicklist:5text:The informant put Luongo in touch with a man she believed was a hit man using the name "Neil." But Neil is actually an undercover cop with the VIPER Unit.

Over the phone, Luongo offered Neil $3,900, half upfront and half after the murder. To be sure that the plot was real, Neil visited Luongo in jail.

"When I leave you here today, it'll be the last time I talk to you until it's done. Okay? So you're 100 percent?" Neil can be heard asking Luongo on undercover footage of the visit.

"Okay," Luongo told Neil.media:28067271

quicklist:6text:Not knowing who else Luongo may have contracted to kill Calderon, the deputies moved quickly to brief Calderon on the situation.

Just hours after meeting Luongo, the fake hitman and the VIPER team made a plan to fake Maria's death. Neil offered to show Luongo photos of Calderon's body so that she would have proof it was done.

Police took Calderon to the swamps of the Florida Everglades to stage photos of her death. The Broward County Sheriff's Office hired a professional makeup artist to help make Calderon's supposed murder look authentic.

Makeup was used to make it appear as if Calderon had a gunshot wound to her head, and they bound her hands with duct tape, which they also placed over her mouth.media:28067337

quicklist:7text:The VIPER team then had the grisly photos to convince Luongo that Calderon was dead. Neil told Luongo that he needed to leave town and sent a friend, who is actually another member of the VIPER team, in his place.

He showed Luongo the photos of Calderon's murder and asked her to sign them to verify that she saw them.

"Other than maybe relief, she's not upset about a person losing their life one bit, no visible signs of being upset at all," the undercover officer playing the friend told "20/20."

Afterwards, police say Luongo even called Neil to thank him for a job well done.media:

quicklist:8text:Two weeks later, Luongo was back in a Florida courtroom and slapped with new attempted murder charges for her alleged plot to have Calderon killed.

Combined with her previous charge in the murder of Pat Viveiros, Luongo, if convicted, faces the death penalty.

Luongo and her attorney declined a request for an interview from "20/20."media: