Former Detroit Police Deputy Chief James Tolbert, left, and Davontae Sanford.
DETROIT (WJBK) - Davontae Sanford is back home tonight after spending nearly nine years in prison for crimes he didn't commit.
The question is how did it come to this in the first place?
"It called into question the building blocks of our case," said Wayne County Prosecutor Kym Worthy.
Wayne County Prosecutor Kym Worthy says it all came down to a statement that allowed Davontae Sanford to go free after he was wrongly imprisoned for a quadruple murder he did not commit.
And that statement she claims, came from then-Detroit Police Deputy Chief James Tolbert.
"That's why this case was charged in the first place," she said. "Because we thought we could prove it in court beyond a reasonable doubt."
But doubt set in after Michigan State Police began investigating and accused Tolbert of perjuring himself.
Initially, according to the transcripts, a sketch of the house where all of the four people who were shot and killed was drawn by Davontae Sanford.
"Deputy Chief Tolbert as I indicated before, testified that Mr. Sanford drew the sketch from a blank piece of paper, and then signed it," Worthy said.
In Sept. 2015 during another hearing, Tolbert testified he was the one, who drew the sketch.
Attorney: "So who drew the house here?"
Tolbert: "I drew the house."
Attorney: "Okay you drew the house."
Tolbert: "I said this is the house where were the bodies."
Attorney: "And so he just draws the bodies in there."
On Thursday Worthy said: "Deputy Chief Tolbert, at the time with the Detroit Police Department responded to questions that undermined his prior testimony under oath (that Mr. Sanford created a sketch from a blank piece of paper)."
It was a major piece of evidence but Worthy stressed there was so much more that led to the charges including tracking dogs, gun residue and Sanford's confession.
FOX 2 obtained the video interrogation with Sgt. Russell who went over Sanford's statement (a portion of it is included in the video above).
Two weeks after Sanford was sentenced to life in prison - Vincent Smothers admitted to the four murders on Runyon and several other murders.
But it took nearly nine years and Tolbert's statement that finally forced the prosecutor to drop the charges and allow Sanford to go free.
FOX 2 legal analyst said if the former deputy chief is charged with perjury, he could now be facing life in prison.
"Perjury is lying and when you lie under oath in a court case when your testimony could send someone in prison for life," Charlie Langton said. “That’s really bad and the penalty for lying in that kind of case is life for you, for lying."
The Wayne County Prosecutor's Office has received the perjury warrant for Tolbert. Worthy said they are in the process of determining whether the former deputy police chief should be charged.