In the summer of 2017, Helen Hargan, 24, was living with her mother, Pam, 63, and her oldest sister, Megan, 34, in McLean, Virginia. Helen was looking forward to moving into a home Pam was generously buying for her.
Helen Hargan and Carlos Gutierrez
Around 11:30 a..m on Friday, July 14, 2017, Helen called her boyfriend, Carlos Gutierrez, who lived in Dallas, Texas. According to Gutierrez, Helen had shocking news: her sister Megan had just told her that she killed their mom. Gutierrez said Helen told him to remain calm and quiet. She even told him to "shut up and act like everything is normal."
The 911 call
Around 1:15 p.m., Helen stopped answering her phone. Carlos Gutierrez grew anxious and called Fairfax County, Virginia, 911 Dispatch. He told the 911 dispatcher what Helen had told him about Pam and that Helen "won't answer her phone and I'm thinkin' maybe somethin' bad happened to her, too." Gutierrez would later say that he felt authorities were giving him the runaround that day.
Entering the home
When patrol officers arrived a little before 3 p.m., they first discovered Pam Hargan. She was found face-down on the floor of the mudroom with a blanket placed on top of her. Her cell phone was found partially on top of the blanket.
A shocking discovery
When patrol officers went upstairs, they discovered Helen Hargan in the bathroom. She was dead, and there was a rifle between her legs.
Around 5 p.m. that day, Helen's sister Megan Hargan told investigators that when she left the home in the early afternoon, her mother was alive. Megan said that Helen and Pam had been fighting.
"This morning, my mom let Helen know that she was canceling the contract on the house she's building her, because she truly believed that Helen was gonna try to move Carlos into the house and my mom didn't want him being there."
By 8 p.m, a Fairfax County police spokesman had told the media what the police had told the Hargan family: Helen's wound looked self-inflicted. This looked like a murder-suicide.
Detective Byerson steps in
Lead Homicide Detective Brian Byerson wasn't convinced that Helen had taken her own life. As he walked through the scene, he made a decision: "Wait," he tells "48 Hours" correspondent Peter Van Sant. "You will make mistakes … if you make assumptions before you actually do the work."
Detective Elliott examines the scene
Crime scene Detective Julia Elliott combed the Hargan house for clues. She says that there were several pieces of evidence that caught her attention.
Looking at Pam's crime scene, Det. Julia Elliott noticed something unusual about the location and position of Pam's cellphone. "It's lying on top of the pool of blood and the blanket," says Det. Elliott. "It certainly wouldn't fall on top of the blanket and on top of the blood once you were already covered up."
This suggested to Det. Elliott that the phone was "placed there by someone."
A closer look at the rifle
Examining Helen's death scene, Det. Elliott noticed there was a lot of blood on the floor, but very little blood on the rifle. "You would expect that if the rifle had been sitting there as she bled so heavily, it would also have blood on it" she says.
Helen's phone was found on the bathroom counter near her. Although Helen had used her cellphone that day to talk and text with Carlos Gutierrez, there were no fingerprints on it. "What we found was what looked like swipe marks," says Det. Elliott. "As if someone had taken their hand and wiped off the front of the screen."
On Saturday, the day after the shooting, Helen's autopsy report came in. It revealed a gunshot wound to the top of her head with the bullet path leading down into her neck. This confirmed for Det. Byerson that Helen's death was not a suicide. "It tells us that someone else pulled the trigger," he says.
Capital One Bank
On Monday, July 17, Det. Byerson received a voicemail from Capital One Bank. Someone had tried to transfer more than $400,000 from Pam Hargan's account on the day before and the day of her murder. When Pam learned of the fraud, she did not know who the fraudulent caller was, and she immediately froze her account. She then sent her daughter Megan – seen here in the black T-shirt – to the bank to confirm that her mom's account was frozen.
The almost confession
On July 19, five days after the shootings, Det. Byerson brought Megan Hargan in for an interview. It would last more than four hours. Byerson says that Megan admitted she was the one attempting to transfer funds from her mom's account, but she was adamant that she didn't kill her family.
Despite Det. Byerson's lingering suspicions, Megan left the police station that day a free woman.
On November 9, 2018 -- 16 months after the deaths of Pam and Helen -- Megan Hargan was arrested.
"Murder investigations can be extremely complex … you not only have to be sure, you have to be right," Det. Byerson explains when asked about the delayed arrest.
More than three years after her arrest for the murders of her mother and sister, Megan Hargan went on trial. Prosecutors tell the jury Megan was so desperate for the money to purchase her own house, she killed her mom and then killed Helen to keep her quiet. They say she then staged the scene to look like Helen had killed her mom and then herself
"Toe on the trigger" defense
The defense argued that Helen – not Megan – was the killer. They claimed that Helen was mentally unstable and furious at her mom for threatening to take away her home if Helen didn't break up with Carlos Gutierrez. The defense tells the jury that after killing Pam, Helen used her toe to pull the rifle's trigger.
The prosecution says there is no evidence that Pam Hargan was going to cancel the contract on Helen's new house.
Crime scene reconstruction
Forensic Specialist Iris Dalley Graff was hired by the prosecution to reconstruct Helen Hargan's shooting scene. After analyzing photos of the scene, Graff does not believe that Helen took her own life.
However, Graff does concede that Helen's legs are long enough to have reached the trigger.
After a three week trial, it takes the jury less than two days of deliberations to reach a verdict. Megan Hargan is found guilty of the murder of her sister, Helen, and mother, Pam. The jury recommends a sentence of life in prison on each murder count.
On Nov. 9, 2022, a judge overturned Hargan's double murder conviction, citing juror misconduct. The ruling came after a juror tried to reenact Helen Hargan's shooting using a rifle, and during deliberations told other jurors that the defense's theory of the case was not possible. Megan Hargan's retrial is scheduled for Sept. 5, 2023.
On Sept. 22, 2023, a jury found Megan Hargan guilty of two counts of first-degree murder for the shooting deaths of her mother Pamela and sister Helen.