The charges pile up against a pair of former Virginia police chiefs, a Cleveland DEA agent has some explaining to do, and so does a Houston crime lab tech who didn't follow procedures and wouldn't take a drug test. Let's get to it:

In Houston, more than 200 drug cases are in jeopardy after a lab technician is accused of "failing to properly secure drug evidence." It's only the latest scandal for the city's troubled crime lab, which has been under scrutiny for the past five years over faulty DNA testing that sent people to prison, the drug and alcohol testing division being shut down after its director failed a proficiency test, and evidence from thousands of cases being improperly stored in the evidence rooms. In the latest blow, the Houston Police Department announced Tuesday that lab tech James Carpenter had been relieved of duty with pay. Carpenter, who worked in the drug lab since 2002, had been recently warned about missing work, and investigators sought him out last week after receiving reports that he "was not handling evidence in compliance with lab protocols." When Carpenter refused to give a formal statement or submit to a drug test, he was suspended. Now, all his work for the past six months -- some 200 drug cases -- is under review.

In Richmond, Virginia, two former Southwest Virginia police chiefs already facing charges were arrested again last week on new drug charges. Former Damascus Police Chief Anthony Steven Richardson was charged with conspiracy to distribute drugs, obstruction of justice, possession of drugs and possession of firearms. Richardson, 40, already faced seven felony counts from June, including distributing methamphetamine. Former Chilhowie Police chief Dwayne Sheffield was charged with distribution of drugs, child abuse/neglect and conspiracy to distribute drugs. Sheffield, 37, already faced charges from May of committing sex crimes against a 17-year-old girl during a Halloween haunted house that raised money for sexual assault victims. The new charges resulted from an investigation by state, local, and federal law enforcement officials, and officials said the drugs involved were mainly methamphetamine and marijuana. Sheffield's wife, Nancy, was also charged with drug distribution, conspiracy, and child abuse/neglect.

In Cleveland, a DEA agent is under scrutiny after one of his informants admitted sending dozens of people to prison with false testimony. Informant Jerrell Bray told authorities in May he had made up testimony and lied on the witness stand in numerous cases, resulting in the dropping of charges in two cases and the release of one prisoner so far. Many more could come. DEA Agent Lee Lucas, who has a reputation as gung-ho drug fighter, is Bray's handler. The testimony of both Bray and Lucas in numerous drug cases is being challenged. Look for more to come out in coming weeks and months on this one.