BOSTON - As churches paused to mourn the dead and console the survivors of the Boston Marathon bombing Sunday, the city's police commissioner said the two suspects had such a large cache of weapons that they were probably planning other attacks. The surviving suspect remained hospitalized and unable to speak with a gunshot wound to the throat.

After the two brothers engaged in a gun battle with police early Friday, authorities found many unexploded homemade bombs at the scene, along with more than 250 rounds of ammunition. Police Commissioner Ed Davis said the stockpile was "as dangerous as it gets in urban policing."

"We have reason to believe, based upon the evidence that was found at that scene - the explosions, the explosive ordnance that was unexploded and the firepower that they had - that they were going to attack other individuals. That's my belief at this point," Davis told CBS's "Face the Nation." On "Fox News Sunday," he said authorities cannot be positive there are not more explosives somewhere that have not been found. But the people of Boston are safe, he insisted.

The suspects in the twin bombings that killed three people and wounded more than 180 are two ethnic Chechen brothers from southern Russia - 19-year-old Dzhokhar Tsarnaev and his 26-year-old brother, Tamerlan. Their motive remained unclear.

The older brother was killed during a getaway attempt. The younger brother, Dzhokhar Tsarnaev, was still in serious condition Sunday after his capture Friday from a tarp-covered boat in a suburban Boston backyard. Authorities would not comment on whether he had been questioned.

Sen. Dan Coats of Indiana, a member of the Senate Intelligence Committee, said Tsarnaev's throat wound raised questions about when he will be able to talk again, if ever.

It was not clear whether Tsarnaev was shot by police or inflicted the wound himself.

In the final standoff with police, shots were fired from the boat, but investigators have not determined where the gunfire was aimed, Davis said.

In an interview with The Associated Press, the parents of Tamerlan Tsarnaev insisted Sunday that he came to Dagestan and Chechnya last year to visit relatives and had nothing to do with the militants operating in the volatile part of Russia. His father said he slept much of the time.The younger Tsarnaev could be charged any day. The most serious charge available to federal prosecutors would be the use of a weapon of mass destruction to kill people, which carries a possible death sentence. Massachusetts does not have the death penalty.

Across the rattled streets of Boston, churches opened their doors to remember the dead and ease the grief of the living.At the Cathedral of the Holy Cross in South Boston, photographs of the three people killed in the attack and a Massachusetts Institute of Technology police officer slain Thursday were displayed on the altar, each face illuminated by a glowing white pillar candle.

"I hope we can all heal and move forward," said Kelly McKernan, who was crying as she left the service. "And obviously, the Mass today was a first step for us in that direction."A six-block segment of Boylston Street, where the bombs were detonated, remained closed Sunday. But city officials were mapping out a plan to reopen it.

Mayor Thomas Menino said Sunday that once the scene is released by the FBI, the city will follow a five-step process, including environmental testing and a safety assessment of buildings. The exact timetable was uncertain.Boston's historic Trinity Church could not host services Sunday because it was within the crime scene, but the congregation was invited to worship at the Temple Israel synagogue instead. The FBI allowed church officials a half-hour Saturday to go inside to gather the priests' robes, the wine and bread for Sunday's service.

Trinity's Rev. Samuel T. Lloyd III offered a prayer for those who were slain "and for those who must rebuild their lives without the legs that they ran and walked on last week.""So where is God when the terrorists do their work?" Lloyd asked. "God is there, holding us and sustaining us. God is in the pain the victims are suffering, and the healing that will go on. God is with us as we try still to build a just world, a world where there will not be terrorists doing their terrible damage."