But when they were on the phone, the conversation suddenly stopped.
"Her mother stopped the attack," Salt Lake City Police Department spokesman Sgt. Said Brandon Shearer. "And then the phone was dead."
The incident was part of what police in the house called a "very violent and brutal attack," Shearer said.
As soon as the phone was dead, Bagshaw's mother contacted a neighbor and the police. Officers called for a social welfare check-up at the residence and discovered that the teenager was dead in the house, according to the police station.
It was unclear whether the attacker was waiting in the house before Bagshaw arrived. According to Shearer, the police have not yet reported the official cause of death of Bagshaw.
Authorities have identified Shaun French, 24, as a suspect in Bagshaw's assassination. He was arrested on Wednesday.
French was known to the family, Shearer said. He also has an active criminal arrest warrant for three cases of unlawful sexual acts with a minor, from previous contact with the victim, police said.
One of the reasons why the order was enforced was to relieve Shearer of French extradition to Utah if he were taken out of the country.