Evidence from the gun allegedly used to kill Baltimore police Detective Troy Chesley was contaminated by an employee of the city crime lab, the Police Department revealed Wednesday.

Rana Santos, the lab’s DNA technical leader, made the revelation during testimony in the murder trial of Brandon Grimes in Baltimore City Circuit Court.

Recommended Stories

‘Cruel and cowardly’ cop-killer sentenced to life, no parole

DNA evidence casts doubt on conviction

False-confession expert?s testimony barred from Innocence Project case`