Concern about gravesite vandalism has weighed on the families of other notorious killers, including one of the gunmen in the 1999 Columbine High School attack in Colorado. Dylan Klebold's family had him cremated, according to the Rev. Don Marxhausen, who presided over his funeral.
"He couldn't publicly go in a cemetery," Marxhausen said. "There is that issue of people who would desecrate."
Marxhausen said a policeman escorted him to the funeral, and others took circuitous routes to avoid being followed by the media. Marxhausen's role at the funeral sparked an outcry and he later lost his position as pastor at the St. Philip Lutheran Church in Littleton, Colo., but he said he does not regret his role.
"Christ always goes where it's darkest. You do your job," he said.
The family of the other Columbine shooter, Eric Harris, has never publicly revealed his final resting place.
James Fox, a professor of criminology at Northeastern University, said it is not unusual for notorious criminals to be buried in undisclosed locations to keep away the media, protesters and potential vandals. He said there could be an increased risk of a gravesite becoming a target in Lanza's case because he took his own life and was not punished.
"There is the potential for people to express anger, hostility, rage at the symbol of a person's grave if it were known," he said.
In a statement issued a day after the Newtown massacre, Peter Lanza said the family was struggling to make sense of what happened and "trying to find whatever answers we can." He also expressed sympathy for the victims' families.
Associated Press writer Pat Eaton-Robb contributed to this report from Newtown.