A routine traffic stop led state police to uncover a drug trafficking operation, law enforcement said Thursday.

Massachusetts State Police announced the arrest of a suspect on heroin trafficking charges after he was pulled over for driving through a stop sign. 

The incident reportedly occurred just before 6 p.m. Wednesday. 

A state trooper saw a 2009 Camry pass through a stop sign on Old Road in Boston.

Driver Alex Hernandez, 37, of Roxbury, allegedly had at least four pounds of heroin inside a container on the car, more on his person, and $1,757 in cash.

Hernandez is now charged with heroin trafficking, possession of false RMV documents, furnishing a fake name, failure to stop and failure to signal. His bail is set at $50,000, police said.