Free, the British creator of The Slow Mo Guys channel - which has more than 10 million subscribers and a billion video views - was forced to hide in a bedroom cupboard with Turney and call police, according to court documents seen by The Albuquerque Journal.
It reported the gunman from New Mexico, who was named as Christopher Giles, drove 11 hours to the couple's home in Austin, Texas, late last month and planned to harm the internet personalities after "developing a fondness" for 30-year-old Turney - a cosplayer and vlogger with more than a million Facebook followers.
The paper said a warrant searching Giles' phone and other electronic devices found more than a thousand notes about Turney and 29-year-old Free, who rose to prominence with his series of slow-motion videos.
The man is thought to have broken into the couple's home after shooting a glass door at the property, prompting the couple to find a hiding place.
When officers arrived, they had a brief exchange with Giles in the driveway of the property. He reportedly fired his gun and an officer is thought to have returned fire.
Giles later died of his injuries but it has not yet been confirmed whether the gunman died from police gunfire or a self-inflicted wound.
Responding to the incident on Twitter, Free thanked officers and fans for their support.
"I just wanted to say thanks for all the support and concern regarding the recent incident. It's been a rough time for Meg and myself the last few weeks but we are doing ok," he wrote.
"I want to give a huge thanks to @Austin_Police for the amazing response time. (Heart emoji) you all."
Turney wrote: "Thank y’all so, so much for each and every kind message today and a special thank you to the @Austin_Police for their quick response that night and their ongoing support during this difficult time. Heart you guys so much."