When they arrived, they discovered that Blessing had shot and killed her son.
Blessing told detectives that she had been thinking for several days about her son’s intention to put her in an assisted living facility because he said she had become “difficult to live with.”
ABC15 in Phoenix reported at the time that she made an ominous statement when she confronted him: "You ended my life, so I'm taking yours."
Police officials said Blessing confronted her son with two pistols in the pockets of her bathrobe. During the confrontation, she pulled out one of the handguns and fired several shots, killing him.
Thomas Blessing's girlfriend struggled with the elderly woman over the weapon and knocked it from her hand, a Sheriff's Office news release said. Blessing then pulled out her second gun and tried to point it at the girlfriend, but the younger woman knocked that one from her hands as well.
The woman ran from the condo and got help.
The Republic reported that court records indicated Blessing pulled the handguns on her son and his girlfriend as they lay in bed, asleep. After the shooting, she sat in a recliner in the living room and awaited deputies.
She told the deputies who responded that she wanted to kill herself, as well, but did not have another gun after her son's girlfriend disarmed her, the newspaper said.
Police officials said deputies had been called to the condo multiple times prior to the shooting for arguments between Anna and Thomas Blessing.
"There were communications between the parties expressing the frustration in the relationship, even to the point where both had expressed a concern that the other party could become violent," Maricopa County Sheriff Paul Penzone told the Republic after Anna Blessing's arrest.
Deputies did not intervene, despite those fears. After Thomas Blessing’s slaying, a total of 13 guns, including two belonging to Anna Blessing, were found in the home.
"If we failed in any way, shape or form, that is unacceptable," Penzone said following the shooting, according to the newspaper. "But we're not ultimately the ones responsible when an individual decides to take the act of using a firearm or other weapon to take another life. It is that individual's responsibility; they own that act."
An internal review has since determined that deputies acted appropriately, a department spokesman told the Republic.