NEWTOWN, Connecticut: Most children in Newtown returned to classes on Tuesday (Wednesday in Manila) for the first time since last week’s massacre, but survivors of the shooting stayed home and their school remained a crime scene.

Four days after a disturbed 20-year-old shot his mother, then 20 first graders and six staff at Sandy Hook Elementary School, the debate over America’s lax gun laws hit a new pitch with President Barack Obama coming out in support of a new bill that would ban assault weapons.

Adam Lanza’s principal firearm in last Friday’s massacre was a military-grade Bushmaster semi-automatic rifle, exactly the kind of gun that would be banned if the Obama-backed bill gets past Congress—something far from guaranteed.

But in Newtown, there were more immediate worries as yellow school buses rolled through thin drizzle at the delayed start of the school week. It was only a baby step back toward normality in a town that had been known for low crime and a tight sense of community until the shootings.

Classes began up to two hours late and extra security was posted outside buildings. But survivors of the Sandy Hook massacre stayed home.

Bill Hart, of the Newtown Board of Education, tweeted that “no date has been set” for reopening the school.

US media reported that Newtown Superintendent of Schools Janet Robinson had sent a letter to Sandy Hook parents, inviting them to visit the former Chalk Hall school in neighboring Monroe and saying classes would start there for survivors in January.

“We need to tend to our teachers’ and students’ needs to feel comfortable after this trauma in this new place,” the letter said, according to Fox News and CNN.

Detectives and forensic scientists continued to comb the school building in a painstaking attempt to piece together what happened when Lanza opened fire. But the police remain tight-lipped about what they’ve found that might explain why Lanza, who had no history of violence, snapped.

Searches have concentrated on the school, but also the house where Lanza lived with his mother Nancy—and where he shot her at the start of his killing spree.

Among the items being examined are the rifle and pistols that Lanza carried and which were owned by his mother. There have also been reports that the hard drive to his computer is getting close attention.

With the country still on edge after the Newtown rampage, nerves were rattled in the western state of Utah, where an 11-year-old boy was charged with possession of a deadly weapon after taking a gun to school, saying he was worried about protecting himself.