Michael Ross, 45, was to have been put to death before dawn Wednesday for killing four women in Connecticut. He was sentenced to death in 1987 and again in 2000 and had waived further appeals.
But U.S. District Judge Robert Chatigny early Monday afternoon told Ross's attorney, "I think it would be humane if you were to inform your client ... he's not going to be executed this week," the Hartford Courant reported on its Web site.
The attorney had argued Ross was mentally incompetent to call off his appeals and said the effects of 20 years in prison caused Ross to make that decision.
Authorities claim Ross killed eight women -- six who were 14-17 years old, a 23-year-old and a 25-year-old -- between May 1981 and June 1984. Most of the victims were sexually assaulted.
Although the U.S. Supreme Court declared death sentences do not violate the Eighth Amendment to the U.S. Constitution, allowing executions to resume in 1976, there has not been an execution in New England since 1960.