Police found no weapon, no sign of a struggle. There was little physical evidence to make a case and no witnesses. There was just a father in a jail cell who said that he did not see his son, 5-year-old Giovanni Gonzalez, on the weekend he disappeared three months ago.
In cases like this, investigators say, authorities can do little but wait for a break.
"In order to have a murder charge, you have to prove someone has been murdered, so you need a body," said Thomas J. Foley, former colonel of the State Police.
But a body was missing in this case, and so was another element that former prosecutors and law enforcement officials said is crucial to solving a case: public pressure.
Investigators began searching for Giovanni Aug. 17, the day his mother, Daisy Colon, went to pick him up after a weekend at his father's home in Lynn. When there was no sign of Giovanni, Colon called the police. Detectives found Ernesto Gonzalez, who denied having seen his son that weekend, though the father was seen with his son at a therapist's office Aug. 16.
Investigators began an intensive search, looking for Giovanni in wooded areas, cemeteries, and empty buildings in Lynn. They searched the father's apartment and found a blood-stained mop and blood on the cap of a cleaning product, but later determined that the blood was not Giovanni's. Authorities repeatedly urged anyone with information to come forward, while Ernesto Gonzalez, charged with child endangerment, was held behind bars on $500,000 cash bail.
There were no new major leads, and the case quickly faded from public view.
"Without public attention being brought to an unsolved case, the likelihood of it ever being solved diminishes," said Timothy M. Burke, a former homicide prosecutor with the Suffolk district attorney's office. "Almost invariably, someone out there knows more than they have been willing to say, and without the public pressure, it just drifts into oblivion."
Yesterday, more than three months after the boy was reported missing, Ernesto Gonzalez told a Globe reporter that he stabbed his son to death in his kitchen, dismembered the body in the bath tub, and disposed of the remains in dumpsters.
Police are trying to determine whether he is telling the truth. That such a break came in a confession to a reporter does not surprise law enforcement officials, who say police are not allowed to question suspects who have invoked their right to remain silent.
"He has Fifth Amendment privilege," said Robert M. Griffin, a former chief of superior court prosecution for the Suffolk district attorney's office. "I'm assuming the attorney has told him not to speak to the police. And what are the police going to do? At that point, they've hit a stone wall."
In most cases at that point, police would turn to the public. But grabbling the public's attention in cases in which a parent is suspected of taking a child is extremely difficult, said Richard Rosenfeld, a criminologist at the University of Missouri in St. Louis.
"The ones that tend to attract publicity are ones in which it's determined that the child is kidnapped by a stranger," he said.
The fact that Giovanni is Hispanic and from one of the state's poorer cities could also be a factor, Rosenfeld said. "I think cases in which young, white, middle-class children are kidnapped are likely to attract more publicity," he said.
And so Gonzalez sat in jail, awaiting trial on the child-endangerment charges, and with each passing day the chances of charging him with facing anything more serious became increasingly slim.
Griffin said police in a case like this can end up hoping for the seemingly unlikely development, that a suspect begins to feel a need to talk.
Michael Levenson can be reached at mlevenson@globe.com.
