He found his daughter dead at the bottom of the stairs.
"I walk in and Janae's on the floor, and her clothes are all torn up and stuff," Gagnier said.
The Medical Examiner's office determined Gagnier died by "strangulation and traumatic concussion."
The Richmond Police Department on Monday identified the suspect in her killing as 34-year-old Kevin Alexander Accorto, whose last known address was in Florida. The medical examiner determined he stabbed himself to death.
Mark Gagnier said he found Accorto upstairs.
"I go upstairs, guy upstairs with a knife in him, still alive," the father said.
Richmond police have yet to determine a motive in the killing and an investigation is ongoing.
Police said Gagnier and Accorto had no personal relationship, and her parents said they believe he was crazed Instagram follower.
"Unfortunately, someone basically was stalking, and killed my baby," said her mother, Jeanetta Grover.
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- Associated Press