NEWTOWN, Connecticut - The 20 children killed at a Connecticut elementary school on Friday in one of the worst mass shootings in US history were all aged six and seven, according to a list of victims' names released on Saturday.A Jewish child was identified as the youngest of the 26 victims killed in the Sandy Hook Elementary School shooting massacre in Newtown, Connecticut.Christmas Tree memorialTown fire officials set up 26 Christmas trees, decorated with stuffed animals, near the school as a memorial to the victims - many of whom were children who may have been hoping for such toys as their own holiday presents."These children were so young, so innocent," said Mary Fellows, 49, who attended a midday memorial service at a church near the school. "I just can't imagine." Rabbi Shaul Paver said he had spent time with Veronika Pozner, whose 6-year-old son Noah, was among the victims."She said that she didn't know how she was going to go on, and we encouraged her to focus on her other four children that need her and not to try to plan out the rest of her life, just take a deep breath right now," Paver said.Motives emergingPolice earlier said they had assembled "some very good evidence" on the killer's motives."Our investigators at the crime scene ... did produce some very good evidence in this investigation that our investigators will be able to use in, hopefully, painting the complete picture as to how - and more importantly why - this occurred," Connecticut State Police Lieutenant Paul Vance told reporters.Yale-New Haven Hospital opened a crisis-intervention center in the wealthy suburb of 27,000 people about 80 miles (130 km) from New York City.The incident also stood to revive a debate about US gun laws.The killer's mother, Nancy Lanza, legally owned a Sig Sauer and a Glock, both handguns commonly used by police, and a military-style Bushmaster .223 M4 carbine, according to law enforcement officials, who also said they believed Adam Lanza used at least some of those weapons."We're investigating the history of each and every weapon, and we will know every single thing about those weapons," Vance said.The death toll exceeded that of one of the most notorious U.S. school shootings, the 1999 rampage at Columbine High School in Littleton, Colorado, where two teenagers murdered 13 students and staff before killing themselves.JTA contributed to this report.First grade student Noah Pozner, the youngest of the victims murdered on Friday, had just turned 6 years old November 20; he will be laid to rest on Sunday.Israeli news site Ynet reported that Pozner's twin sister is also a student at Sandy Hook but survived the shooting.Rabbi Shaul Praver of Temple Adath Israel in Newtown told NPR Weekend Edition host Scott Simon that he spent Friday -- which he termed "the day from Hell" -- consoling Pozner's mother, who is a member of the synagogue."I told the mother that was grieving that I personally believe in the eternity of the soul, and I believe that she will see her son again," Praver said. "Other than that theological comment, the rest of it was getting her to think about taking a breath and not trying to plan the rest of her life out right now, because she says, 'What am I going to do without my baby?'" Praver was among the clergy, social workers and psychologists who arrived at a firehouse near the school where many of the victims and their families congregated after the shooting. On Saturday morning, Adath Israel held a community prayer service.In response to the question of why such tragedies happen, Praver replied: "I don't know the answer to that. I never try to present a theological answer to that. I think what's more important is to have compassion, humanity and hold someone's hand and hug them and cry with them." Praver, who ended his NPR interview with a plea for listeners to pray for the families affected, also said that another friend of the congregation was killed.The brazen attack, in which a heavily armed 20-year-old gunman forced his way into Sandy Hook Elementary School and shot his victims multiple times, shattered the quiet, suburban community of Newtown, Connecticut.The state's chief medical examiner, Dr. H. Wayne Carver II, described the attack that left a total of 28 people dead, including the shooter and his mother, "the worst I have seen." Asked to describe the young victims - one of whom had just celebrated her seventh birthday on Tuesday, Carver said, "They were wearing cute kid stuff." "They were first graders. It's the kind of stuff you'd send your kids or your grandkids out the door to first grade in," he told reporters.All the shootings he was aware of were committed with a rifle, Carver said.The dead included eight boys, 12 girls, and six women aged 27 to 56, authorities said."All the wounds that I know of at this point were caused by the long weapon," Carver said.US President Barack Obama plans to travel to Newtown, Connecticut, on Sunday to meet with families of the victims of the shooting that was one of the deadliest such incidents in the nation's history.The White House said in a statement Obama will speak at a 7 p.m. EST Sunday interfaith vigil for families of the victims and other students from Sandy Hook Elementary School, which was attacked on Friday by a heavily armed gunman.In his weekly radio and internet address earlier on Saturday, Obama said it was time to "take meaningful action to prevent more tragedies like this."But he stopped short of specifically calling for tighter gun-control laws.The list of names released did not include the shooter, identified by law enforcement sources as Adam Lanza, or his mother, who Carver confirmed was killed nearby.Adam Lanza killed his mother, Nancy, at her home and then drove to the school where he continued his shooting, law enforcement officials said. Multiple guns were registered to Nancy Lanza and some of them were found at the scene, a Connecticut law enforcement official said.Obama, who a day earlier was moved to tears on national television by the tragedy, called for "meaningful action to prevent more tragedies like this," but stopped short of specifically calling for tighter gun-control laws.The nation has experienced many mass shootings, but rarely have the victims been so young.