The proposed legislation, among other things, would stiffen penalties for threatening or harming a witness, and allow some out-of-court statements to be used as evidence at trial.
"Unless we take steps to protect our witnesses, the whole criminal justice system will crumble."
The bill is scheduled for a state Senate committee hearing Wednesday.
Defense attorneys complain that the bill, if it becomes law, would strip a defendant of the right to cross-examine a witness and may be unconstitutional.
The bill would:
Currently, witness intimidation is a misdemeanor that carries a maximum five-year prison sentence, and the statute is rarely used by prosecutors because, they say, the cases are difficult to prove and the penalty is paltry.
Adams, the homicide prosecutor, said that in 90 percent of his cases, witnesses are afraid to testify or lie on the stand.
"If this [bill] passes," he said, "it could be a powerful piece of legislation."
The most critical - and contentious - part of the bill is the exemption to the hearsay rule, which would allow out-of-court statements from witnesses to be used at trial if they are not available because they have been threatened or harmed.
If a witness is assaulted before trial and is incapacitated or unable to be found, a police officer would be permitted to testify as to what that witness said out of court about the case.
Currently, that type of testimony would not be admissible because it would be hearsay.
The bill faces strong objections from defense attorneys, and Michael A. Millemann, a professor at the University of Maryland School of Law, said such legislation is "probably unconstitutional."
"The goal is laudable, but there are too many problems with this approach," Millemann said. "The system will encourage people to be unavailable for trial and encourage police not to find them."