Earlier this year, after the astronauts passed the 60-day mark in space, social media users expressed outrage at the situation, with many calling the extended delay "torture."
It is unclear whether Natalia is an only child, but in the post, Jeff referred to his daughter as "kiddo" and expressed pride in her skills with the weapon.
Despite a lack of evidence, claims that Rupnow was transgender have circulated online, a trend that has become common following school and mass shootings.
Just hours before Rupnow was named as the suspect in Monday's mass shooting in Madison, a social media user claimed to have spoken with the 15-year-old's alleged boyfriend.
"This remains an active and ongoing investigation," police said in a statement. "More information will be released as it is available. We currently need people to avoid the area."