Boston — After 15 years in prison, serving a life sentence for a murder he did not commit, a 42-year-old Massachusetts truck driver is now a free man.
The Aug. 20 release of George A. Reissfelder came nine weeks before Bay State residents will vote on whether to bring back capital punishment.
And foes of the controversial death penalty are losing little time in seizing on the case to build support for their cause. They point out that had the measure been on the books in 1967 when Mr. Reissfelder was convicted of involvement in the fatal shooting of a guard during a payroll robbery, he might long since have been executed.
It is uncertain, however, what impact such arguments - along with the more familiar protests that capital punishment is ''inhuman'' and ''morally wrong'' - might have on the pending proposal. If approved, it would move Massachusetts to the threshhold of becoming the nation's 38th death penalty state.
A similar state constitutional amendment is being pushed in Michigan, but whether it will make the Nov. 2 ballot is uncertain. State election officials have ruled that the proposal, submitted through initiative petition, fell short of the nearly 287,000 voter signatures required.
L. Brooks Patterson, a prosecuting attorney and the measure's prime mover, is now in the federal courts attempting to overturn that finding.
Michigan has not had the death penalty for over a century, having abolished it in 1846. Thus it was not affected by the 1972 US Supreme Court decision which struck down most capital-punishment laws throughout the nation.
Meanwhile in New Jersey, a new measure reinstating the death penalty has been put on the books. But the legislation, signed into law Aug. 5 by Gov. Thomas Kean, does not specify the method of capital punishment, something state lawmakers are expected to come to grips with later this year or early in 1983.
A previous New Jersey death penalty measure, which involved use of the electric chair, was struck down by the Supreme Court along with capital punishment statutes elsewhere. The justices ruled that the execution laws violated the federal constitution's prohibition of cruel or unusual punishment.
Since 1976, when the high court began again allowing the death penalty under separate guilt-finding and sentencing procedures, close to three dozen states have enacted such measures.
Over the past seven years there have been five executions, the latest being that of Frank J. Coppola less than two months ago in a Virginia electric chair. The execution came after justices of the Supreme Court refused to delay action pending a further appeal in his behalf. Although professing his innocence, the one-time police officer had given up his fight for vindication and asked that his sentence not be further delayed.
Execution of another convicted murderer, Charles W. Bass, was to have been carried out in Texas through lethal injection in late August, but an eleventh-hour indefinite stay of the sentence was granted by the Supreme Court.
The 26-year-old convict, sentenced for the 1979 slaying of a Houston city marshal, is one of 146 death row residents in Texas.
Nationally there are 1,058 convicts under capital punishment sentences in 31 states, according to Jack Boger, of the NAACP Legal Defense and Education Fund. The list includes 655 whose convictions have been overturned in court but are under appeal or referred to a lower court for resentencing or a possible new trial.
This count, as of Aug. 20, is 26 percent higher than the same date a year earlier, and includes 1,045 men and 13 women. Of the current total, 52.27 percent are white, 42.16 percent black, 4.54 percent Hispanic, and 1.03 percent other.
Four states account for over half the nation's death-row population - Florida has 181 such inmates, Texas 146, Georgia 117, and California 107. The number of condemned prisoners in the latter state ''has really shot up'' Mr. Boger says, noting that in August 1981 there were 40 fewer.
Today's death row residents range in age from 18 to 80, with the average 30 years old, according to US Census Bureau researcher Susan Schecter-Ryan. During 1981, 228 persons were sentenced to death row and 78, including two of the foregoing, came off either through sentence commutation to a lesser penalty, vacating of the sentence by a higher court, overturned convictions, execution, or death from natural causes.
Not infrequently, new evidence comes to light which entitles a condemned person to a review of the conviction if not a new trial, and, in some instances, freedom.
In acknowleding that innocent people may have been convicted of murder and even given the death sentence, supporters of capital punishment like Massachusetts Gov. Edward J. King hold that wrongfully convicted persons are amply protected from execution through the appeal process.
They contend that only those convicted of the most heinous crimes, such as first degree murder, receive the death sentence.
Henry Schwarzchild, of the capital punishment unit of the American Civil Liberties Union (ACLU), and other death penalty battlers counter that even if justice were even-handed and executions humane, the possibility that an innocent person could be put to death is ample justification for abolition of the penalty.
While the fast-climbing number of death cell occupants is of particular concern to capital-punishment foes, including the ACLU, these foes generally discount recent somber forecasts by federal officials of frequent executions by early next year.
Benjamin Rehnshaw, acting director of the Bureau of Justice Statistics, has observed that time is running out for a record number of death row inmates, and the rate of executions may be ''approximating the more than three a week that prevailed during the 1930s.
Besides Massachusetts and Michigan, states without capital-punishment statutes are Alaska, Hawaii, Iowa, Kansas, Maine, Minnesota, North Dakota, Oregon, Rhode Island, West Virginia, and Wisconsin.