An Arizona resident is on the mend following a brutal assault by an unidentified attacker during a routine dog walk.

Jeff Zimmerman, aged 71, was out for a stroll with his dog in a park on the afternoon of December 13 when a man dismounted his bicycle and launched an unprovoked attack. Fortunately, two bystanders came to Zimmerman’s aid, managing to pull the aggressor away. Zimmerman was subsequently transported to the hospital, suffering from severe injuries. Law enforcement officials informed CBS affiliate KPHO that they had apprehended an individual linked to the attack, though they have yet to disclose further details about the suspect.

Kiera Zimmerman, Jeff’s daughter, shared updates on her father’s condition with KPHO, expressing gratitude towards those who intervened to protect her father, whom she affectionately calls her “ride or die.”

In a GoFundMe campaign she launched to assist with medical expenses, Kiera revealed that her father has been living with a brain tumor for 16 years. The recent assault has exacerbated his health issues, resulting in “severe head injuries, multiple broken bones, and trauma to his right eye.”

During her conversation with KPHO, Kiera expressed her admiration for her father, saying, “He’s literally my ride or die. He truly is the most loving guy, and also the strongest person I’ve ever met.”

Kiera Zimmerman said that her father spent four days in intensive care before being transferred to the trauma unit. In her GoFundMe statement, she said Jeff Zimmerman was “in immense pain and is only at the very beginning of what will be a long and difficult recovery.”

Despite her father’s poor condition, Kiera Zimmerman said that she was “so thankful that he’s alive.” Of the couple who stepped in to help someone they did not even know, she told KPHO, “But the fact that they were like, right place, right time is literally an act of God. Like, that’s incredible. He’s okay because of these two strangers that happened to be there at the right time.”

KPHO reported that the Phoenix Police Department was working toward releasing more information about the suspect they arrested in connection with the nearly fatal attack.