In November 2002, research scientist Sheila Davalloo called 911 from a payphone in Stamford, Connecticut, to report an attack.
The victim was her former co-worker and romantic rival, Anna Lisa Raymundo, whom Davalloo had just viciously stabbed to death — a fact that she left out of her conversation with emergency dispatch.
In hope of throwing law enforcement off her trail, Davalloo fed the 911 operator false information, but her ruse came crashing down when she was arrested for an unrelated attempted murder the following year.
Davalloo, then 33, began plotting Raymundo’s slaying after her lover and co-worker, Nelson Sessler, ended their affair to pursue a more serious relationship with Raymundo. Sessler moved in with Raymundo in late 2002, and the couple became engaged.
Davalloo acted nonchalant, dismissing their relationship as a summer fling, but privately, she was hatching a deadly scheme that she believed would reunite her and Sessler, according to the Stamford Advocate newspaper.
Just past noon on Nov. 8, 2002, a call came into Stamford’s 911 dispatch center. It was a woman’s voice, saying, “I think a guy is attacking my neighbor.”
The caller did not identify herself or the victim, but she said she knew the apartment number.
“I don’t know her name, but she’s my neighbor and she lives in 105 … I saw a guy go into her apartment,” the caller said.
The caller gave the wrong address before correcting herself and then hanging up.
Authorities rushed to the scene, where they found Raymundo dead on the floor. The apartment was a mess, with pools of blood and objects thrown about, indicating a violent struggle.
She had been stabbed multiple times and had also suffered blunt force head trauma, according to the Stamford Advocate.
Working off their anonymous 911 tip, authorities began looking for a male suspect, but they had few clues. They also could not locate the mystery caller, who they hoped would be able to describe the killer in greater detail.
When the caller hung up, the 911 dispatcher called the number back and discovered it had come from a payphone at a restaurant down the street from the crime scene. Police spoke to the manager, but he hadn’t noticed anyone at the payphone, according to court documents.
The caller said she was Raymundo’s neighbor, but investigators canvassed the area and found no one who matched the voice on the 911 call. They were curious as to why the caller mistook her own address and why she placed the call from a payphone down the block instead of her own home.
Police began to believe the caller might have been involved with the murder, but the trail grew colder by the weeks. In the meantime, Davalloo consoled the grieving Sessler, and they rekindled their romance.
Davalloo would not be connected to Raymundo’s murder until March 2003, when she was arrested for the attempted murder of her husband, Paul Christos, whom she had stabbed multiple times in the chest during a sex game at their condominium in Pleasantville, New York.
Christos begged Davalloo to call 911, but instead, she phoned Sessler and invited him over for dinner that night, reported the Stamford Advocate. By checking Davalloo’s phone records, investigators were able to prove she had contacted Sessler that evening, and they soon tied her to Raymundo’s slaying.
In separate trials, prosecutors argued Davalloo had killed Raymundo and attempted to murder her husband in order to be with Sessler.
Her misleading 911 call played a major role during her 2012 Stamford trial, and forensic voice identification expert Tom Owen determined it was Davalloo who had reported Raymundo’s attack, according to the Stamford Advocate.
“Sheila Davalloo is the person that made the 911 call," Owen testified, making his case by using voice analysis software that compared 2002 audio of the call to 2004 recordings made of Davalloo.
A drop of blood left on a bathroom sink handle at the crime scene also was a match for Davalloo’s DNA, reported the Stamford Advocate.
Davalloo was ultimately found guilty of Raymundo murder and sentenced to 50 years in prison, which will be served at a Connecticut prison at the conclusion of her 25-year sentence in New York for the attempted murder of Christos.
To learn more about the two cases and hear exclusive prison interviews with Davalloo, watch “Snapped Behind Bars: Sheila Davalloo,” premiering Sunday, Dec. 1 at 6/5c on Oxygen.
Crime Time is your destination for true crime stories from around the world, breaking crime news, and information about Oxygen's original true crime shows and documentaries. Sign up for our Crime Time Newsletter and subscribe to our true crime podcast Martinis & Murder for all the best true crime content.