Officers shut down a street in northwest Oklahoma City Friday afternoon over concerns that two Oklahoma City police cars had been contaminated with a hazardous material.

The two cars were involved in the arrest Thursday of Preston Rhoads, a suspect in a possible murder-for-hire plot.

Master Sgt. Gary Knight, a spokesman for the Oklahoma City Police Department, said the department learned shortly after noon Friday that two of its cars could be contaminated. Rhoads sat in both of the cars after his arrest Thursday afternoon, Knight said.

Police wouldn’t say what the possible contaminant was.