Out of concern for the families of those murdered by juveniles and in the wake of a high court ruling that the most severe penalty is unconstitutional, state prosecutors are calling on Beacon Hill to make sure juveniles who commit murder spend at least 35 years behind bars.

“It is an understatement to say that victims’ families, whose loved ones were brutally taken from them and had believed they had some sense of finality, are devastated,” Massachusetts District Attorneys Association President Jonathan Blodgett wrote in a letter to legislators on Friday. “Therefore, the Massachusetts District Attorneys Association believes this decision is particularly burdensome to the families of the victims of juvenile murderers, as they are now subjected to the possibility that their loved ones’ killers will be released.”

Blodgett asked for legislation that would increase from 15 to 35 years the time before a person convicted of first degree murder as a juvenile could be eligible for parole.

On Christmas Eve the Supreme Judicial Court followed the lead of a U.S. Supreme Court decision – that all automatic sentences of life without parole for offenses committed by juveniles are unconstitutional – and found that all sentences of life without parole for offenses committed by juveniles are unconstitutional.

"With current scientific evidence in mind, we conclude that the discretionary imposition of a sentence of life in prison without the possibility of parole on juveniles who are under the age of eighteen when they commit murder in the first degree violates the prohibition against 'cruel or unusual punishment'," Justice Francis Spina wrote in the unanimous decision.

The SJC’s decision in the case of Gregory Diatchenko, who stabbed a man to death in Kenmore Square in 1981 when he was 17, said that all inmates sentenced to life without possibility of parole for crimes committed under the age of 18 should be granted a chance at parole.

State law imposes a mandatory sentence of life without the possibility of parole for the crime of first degree murder, however the SJC ruling found that was unconstitutional for murders committed by juveniles.

According to a Parole Board information page, inmates guilty of second-degree murder can be eligible parole after 15 years of imprisonment. The SJC had advised that the punishment for second degree murder should be the basis for dealing with juveniles convicted of first degree murder.

Blodgett, who is the Essex County district attorney, said the Legislature should first address “the lack of distinction in parole eligibility” between first and second degree murder committed by juveniles, and said people who committed first degree murder while under the age of 18 should receive parole eligibility after 35 years.

“Committing first degree murder needs to be dealt with responsibly by the judicial system, and I will be filing legislation with a coalition of senators soon to address the concerns that we share with the district attorneys,” said Senate Minority Leader Bruce Tarr in a statement. He said, “I do believe judges should have the opportunity to impose meaningful and appropriate sentences for first degree murder, and allowing them to do so will require legislative action.”

“It plainly is within the purview of the Legislature to treat juveniles who commit murder in the first degree more harshly than juveniles who commit other types of crimes, including murder in the second degree,” the SJC ruled.

“As a result of our decision today, in the case of juvenile defendants convicted of homicide crimes committed after August 2, 2012, both murder in the first degree and murder in the second degree are mandatory life-sentence crimes with parole eligibility to be set between fifteen and twenty-five years,” Spina ruled in a similar decision also issued Dec. 24, 2013. “Thus, until the statutory sentencing scheme is further amended, sentencing judges effectively will be required to apply one discretionary parole eligibility range to juveniles convicted of two different crimes.”

Other bills have been filed this session that adjust the penalties for murder committed by juveniles. A bill (H 1492) filed by Rep. Brian Mannal, a Barnstable Democrat and defense attorney, would impose a sentence of 10 years to life imprisonment for first degree murder committed by people between the ages of 14 and 18.

A bill (H 1426) filed by Rep. John Keenan, a Salem Democrat and attorney, would grant parole for people who committed first degree murder while under the age of 18 “at the expiration of the minimum term fixed by the court.”

Neither Keenan’s nor Mannal’s bill have yet had a hearing by the Judiciary Committee, according to the Legislature’s website.

Earlier in the month, Rep. Eugene O’Flaherty, the House chairman of the committee and a Chelsea Democrat who is leaving office to head up Boston’s legal department, told the News Service that legislative action would be necessary after the SJC struck down the statutory penalty for first degree murder committed by juveniles.

After seeking to preserve more judicial discretion, Gov. Deval Patrick signed a sentencing reform bill in 2012. The bill reduced the mandatory sentences for non-violent drug crimes while requiring judges to impose the maximum penalties for habitual offenders who commit violent crimes.

"The Senate President and the Speaker have pledged to return to the subject of mandatory minimum sentencing early in the next session. I take them at their word,” Patrick said in a statement July 31, 2012. “When we do, I trust the decisions we make will be based on data about the costs and trade-offs inherent in the choices we make."