LOS ANGELES (CBSLA.com) — Authorities swept through Steven Avery’s trailer on multiple occasions, only to come up empty handed with no evidence.

That is until a Manitowoc County sheriff’s deputy, who was supposed to be recused from the investigation, walked into Avery’s home during the seventh search of the trailer and found Teresa Halbach’s car key sitting in plain sight.

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DNA evidence found on the key only belonged to Avery, which appeared to be strange as the car key was in Halbach’s possession prior to her disappearance.

The defense argued that Halbach’s DNA had to have been wiped clean from the key in order to transmit Avery’s DNA onto the evidence.

According to Strang, prosecutors never directly alluded as to whether or not the infamous key was planted in Avery’s bedroom.

In his closing argument, prosecutor Ken Kratz stated that other evidence that the state possessed would convict Avery of the crime, regardless of where the key came from; thus implying its irrelevance in the case.

“Is that really where we are,” Strang questioned viewers of the panel. “That police planting of evidence, if it occurred, is a ‘so what because he is already guilty’?”

**Video credit: National Center for Audio & Video Forensics