Section 18. Whenever a person is convicted of a first offense under section 13B, 13F or 13H of chapter 265 or for a first offense for the attempt of any of the aforementioned crimes under section 6 of chapter 274, the district attorney, upon motion to the court, may request a hearing after conviction and before sentencing, to determine whether or not such person shall be committed, in addition to any term of imprisonment or probation authorized by said sections, to community parole supervision for life, to be served under the jurisdiction of the parole board as set forth in section 133D of chapter 127. Whenever a person is convicted of a first offense under section 22, 22A, 23, 24, 24B or 26 of said chapter 265, section 3 or 35A of chapter 272 or for a first offense for the attempt of any of the aforementioned crimes under said section 6 of said chapter 274, the elements of which are mitigated by certain circumstances, the defendant, upon motion to the court, may request a hearing after conviction and before sentencing to determine whether or not such person shall receive, in addition to a term of imprisonment or probation authorized by such sections, community parole supervision for life, to be served under the jurisdiction of the parole board as set forth in said section 133D of said chapter 127.

At such hearing, the defendant shall have the right to be represented by counsel, and, if financially unable to retain adequate representation, to have counsel appointed to him. The defendant shall be afforded an opportunity to testify, to present witnesses, to cross-examine witnesses who appear at the hearing and to present information. The rules concerning admissibility of evidence in criminal trials shall not apply to the presentation and consideration of information at the hearing. A finding by the court that such person shall be committed to community parole supervision for life shall be supported by clear and convincing evidence.

In making a determination the judge shall, on the basis of any information which he can reasonably obtain, consider any mitigating or aggravating circumstances including, but not limited to, the defendant's character, propensities, criminal record, the nature and seriousness of the danger posed to any person or the community and the nature and circumstances of the offense for which the defendant is convicted. If the judge finds, by clear and convincing evidence, that no reasons for community parole supervision for life to be served under the jurisdiction of the parole board, as set forth in section 133D of chapter 127, exist, the judge shall not impose community supervision for life on such first offender.

Whenever a person is convicted of a first offense under section 22, 22A, 23, 24, 24B or 26 of chapter 265, or section 3 or 35A of chapter 272 or for a first attempt of any of the aforementioned crimes under the provisions of section 6 of chapter 274, the district attorney may file a motion with the sentencing judge requesting that the defendant not receive community parole supervision for life, and upon receipt of such motion, the sentencing judge shall not impose community parole supervision for life on such first offender.