Hernandez, joined by his attorneys, Harvey Fishbein and Alice Fontier, sat in court opposite prosecutors from the Manhattan District Attorney's Office as jury selection for the criminal case began.
In May 2012, Hernandez confessed to choking the boy to death in New York City in 1979, according to police.
The potential jurors were asked to review a list of 131 names of potential witnesses and disclose whether they knew anyone on the list.
"The publicity surrounding this case is ... unprecedented," said presiding Judge Maxwell Wiley, urging the possible jurors not to read any media reports on the case.
You must "base your decision on what you hear in this courtroom and nothing else," Wiley instructed.
Jury selection is expected to continue at least until the end of the week, with an additional 100 people expected to arrive Tuesday. Ultimately, 12 people will be chosen to serve on the jury. The trial is expected to last approximately two to three months, Wiley said.
Hernandez admitted to luring Etan, who was en route to a school bus stop, into the basement of a bodega where Hernandez worked as a stock clerk and killing him, according to police. The boy's body was put in a garbage bag and thrown away, Hernandez allegedly told authorities. The remains were never found.
Fishbein previously argued that his client falsely confessed and the statements were not reliable because Hernandez has an "IQ in the borderline-to-mild mental retardation range," and had been repeatedly diagnosed with schizophrenia. But a judge ruled in November
that Hernandez's confession would be admissible in court.
The Patz case garnered national attention after the boy went missing, and his picture was plastered on thousands of milk cartons around the country.
In November 2012, a grand jury indicted Hernandez on second-degree murder and kidnapping charges. He pleaded not guilty in court the following month.