2 Suspended After Improper Mass. Crime Lab Tests

State officials have suspended two supervisors at a Massachusetts crime lab where a chemist is accused of mishandling drug evidence.

The Boston lab was closed Thursday after state police say they discovered that the chemist failed to follow testing protocols, potentially exposing thousands of drug convictions to legal challenges. The lab certified drug evidence in cases submitted by local police from around the state.

The Massachusetts attorney general's office is conducting a criminal investigation. The chemist resigned in March during an internal investigation but has not been charged.

The Department of Public Health said Saturday that the division director responsible for the lab has been placed on leave pending the outcome of the investigation.

State police say another supervisor responsible for overseeing the chemist has also been placed on leave.