The father of a 21-year-old man shot by a North Miami Beach officer on Saturday says he's still searching for answers after police alleged his son charged at them with a knife.

"When you hear the news, they tell you they've shot your child. I asked who shot him, they said the police," Roosevelt Joseph's father told CBS News Miami in Creole, declining to share his name or show his face on camera. "No matter who you are, when you hear shooting, you have to ask: is it my child, and is he alive?"

North Miami Beach police say it started with a fake stabbing report

Officers were dispatched Saturday morning to Northeast 164th Street and 16th Avenue after a 911 call claimed someone had been stabbed. Police say Joseph was holding a knife, ignored repeated commands to drop it, and charged at them before an officer fired.

But Joseph's father believes his son had simply gone to visit his aunt's shop nearby. 

"He went to his aunt's and was walking in the area. We were at a funeral in Orlando," he said, explaining that Joseph may not have known his relatives weren't home.

Investigators later said the stabbing report turned out to be false and believe Joseph himself may have placed the call to lure officers.

Joseph's father disputes police version of the incident

The father said he pressed officers on why they fired. 

"I asked why did you shoot him. They said he was aggressive towards them with a knife," he recounted. But he remains skeptical. "There are other ways they could have neutralized him. They are professionals. They have enough information. No matter what weapons someone may have, there has to be another way to stop them."

He added that if his son had been suffering from a mental health issue, police should have responded differently. 

"Even if they have a mental disorder, I think the police could've done something else," he said.

Search for answers at Aventura Hospital

Joseph's father described the confusion he faced when trying to see his son at the hospital. He said security initially denied him access, even after he showed paperwork provided by police. 

"I told them, the person they shot is my son. I am his dad. I came to see him," he said. "Still at this minute I have to become neutral, because I need more information, more details."

Joseph underwent surgery at Aventura Hospital and was last reported in stable condition. No officers were injured.

The Florida Department of Law Enforcement is leading the investigation, and the officer who fired has been placed on administrative leave, which is standard procedure.