She walked into a $1.3 million McLean, Va. home and opened fire, killing her mother before turning the gun on herself. Police said 23-year-old Helen Lorena Hargan pulled the trigger within an idyllic suburban Washington neighborhood Friday. But audio from emergency dispatchers reveals a family boyfriend alerted police to the crime from more than 1,000 miles away.

“Caller is third party, says his girlfriend called him and advised that her sister killed her mother,” a dispatcher for Fairfax County Police said after 2:03 p.m. Friday. “Caller lives in Dallas, Texas and the girlfriend lives out of address 6708 Dean Drive. Caller advises there should be two children also inside of the residence. No one’s answering the phone.”

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Authorities clarified only one child could have been in harm’s way, a seven-year-old girl believed to be the killer’s niece. Police said the girl was with her mother Friday afternoon and was unharmed.

Officers on the scene could be heard over archived online emergency radio feeds tracing a vehicle license plate to the victim, 63-year-old Pamela Denise Hansen Hargan. Police were initially unsure if the armed daughter was alive inside, as family members tried to rush to the scene.

“The ex-husband spoke to a daughter named Ashley an hour ago, who got a call from the original caller, Carlos in Texas, saying that there were shots at the house,” a dispatcher said. “The daughter Megan is en route to the house from Maryland.”

Police have not yet released a motive for the murder, and are awaiting the results of autopsies performed Saturday.