She was seen hugging him during a football practice at the Taylor Sportsplex in Michigan last Thursday (Dec 3).
Hours later, 57-year-old Timothy Obeshaw turned on seven-year-old Emma Watson Nowling and her mother, shooting the duo with his 9mm pistol at the complex's carpark.
He then shot himself dead with his gun.
Both victims were rushed to the hospital, but Emma died later that night from head injuries. Her mother, 37-year-old Sharon Watson, was in serious but stable condition.
Emma's football coach, Mr Mario Scicluna, told the Detriot Free Press that he had seen the girl taking a break from practice to give Obeshaw a hug.
According to local media reports, Obeshaw was a family friend who had taken a liking to Emma. He had lived with Ms Watson and her boyfriend at their home in Belleville before moving to a home nearby.
The police said they were still trying to establish a motive for the shooting.
A news release from the Taylor Police Department said Obeshaw had started becoming mentally unstable and paranoid over the past year. It also found evidence that he believed someone was trying to perform "mind control" on him.