Jury selection begins later this morning in the retrial of Pedro Hernandez in the murder of Etan Patz in 1979. The first trial a year and a half ago ended with a hung jury. NY1's Michael Herzenberg filed the following report.

Jury selection may take nearly a month. First, as many as 400 prospective jurors will be screened to make sure their schedules allow for this three to four month long trial. Then those that pass that part will fill out a 26 page questionnaire that asks things like have you seen, heard or read anything about the widely publicized case and does it affect your ability to be fair and impartial?

Jurors will watch Pedro Hernandez confess four times to strangling Etan Patz in 1979, and dumping him in a nearby alley in SoHo.

Some jurors from the first trial vow to attend this one.  

Eleven jurors voted to convict Hernandez of kidnapping and murder. The holdout questioned Hernandez's mental health and wondered if cops violated the defendant's rights.

The NYPD arrested Hernandez in 2012 after Hernandez's brother-in-law turned him in. 

At the trial, five witnesses said Hernandez had told them he killed someone..

Those confessions dated as far back as the early 1980's but they differed in some key points. 

The defense said Hernandez believed he killed Etan, but that it was a hallucination.

The defense suggested the killer was Jose Ramos, who dated Etan's babysitter. Ramos is in now prison after molesting other children.

Etan's father Stan Patz had thought Ramos was the killer.  But after watching every day of Hernandez’s trial, he says he came to believe in his guilt so much, he and his wife had a judge throw out the wrongful death civil judgment they won against Ramos years ago.

Etan's disappearance shocked the city, scared parents across America into being more protective of their kids, and led to improvements in police procedures.

He was walking two blocks to his SoHo bus stop alone for the first time when he vanished.

Police combed the neighborhood for clues. There's even video of the lead detective going into the local bodega talking with Hernandez's brother in-law behind the counter.

Hernandez was 18, worked as a clerk there and said he lured the boy to the basement with the promise of a soda.

The prosecution this time may try to emphasize how Hernandez's hallucinations were a product of guilt and drug use.

The judge ruled Friday that Ramos can testify if he wants. In previous proceedings he's invoked his fifth amendment right not to incriminate himself.