BOSTON (AP) — A majority of the state's district attorneys are objecting to key aspects of a massive criminal justice bill scheduled for debate this week in the Massachusetts Senate.

In a letter dated Monday, nine prosecutors contend that many of the provisions contained in the legislation would "turn the clock back" on previous efforts by the Legislature to strengthen sentencing and assure the rights of crime victims.

"We should be especially wary of embracing supposedly 'new ideas' that are no more than a return to the old and discredited ways of the past, the district attorneys wrote. Those old policies resulted in the highest crime rates in Massachusetts' history; a massive exodus of businesses, jobs and residents from urban areas where crime hit the hardest; and even the same racial disparities we all decry today."

The six-page letter was addressed to Democratic Senate President Stan Rosenberg and Sen. William Brownsberger, the Senate chairman of the Judiciary Committee, with copies also sent to all other Senate members. The prosecutors noted that they were not opposed to everything in the bill and that some elements of it "hold out promise."

The letter was not signed by Middlesex District Attorney Marian Ryan and Northwest District Attorney David Sullivan.

Objectionable provisions cited by the nine other district attorneys in the letter included a proposed elimination of mandatory minimum sentences for drug offenders, and the retroactive application of those recommended changes that the prosecutors argued could lead to the early release of hundreds of convicted drug traffickers.

The letter also criticized as "both unnecessary and dangerous," proposed revisions to state laws around statutory rape. The Senate bill seeks to decriminalize what are sometimes referred to as "Romeo and Juliet" relationships involving two minors.

The DAs argued that existing laws are clear and already being applied properly by judges and prosecutors who can easily distinguish between consensual sexual relationships and actions that could be considered child rape.

Raising from 18 to 19 the maximum age at which a criminal defendant is considered a juvenile, as the Senate bill would do, could also create a "slippery slope," and leave many young adults less accountable for their actions, the letter stated.

A spokesman for Rosenberg said the Senate leader planned to review the letter but had no immediate comment.

The Senate plans to take up the 101-page bill and more than 160 proposed amendments to it on Thursday.