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.
After the two brothers engaged in a gun battle with police early Friday, authorities surveying the scene of the shootout found it was loaded with unexploded homemade bombs. They also found 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 aren't more explosives that haven't been found. But the people of Boston are safe, he insisted.
The suspects 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, remained hospitalized 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, but several officials have said Tsarnaev's injuries left him unable to communicate, at least for now.
Shots were fired from the boat, but investigators haven't determined where the gunfire was aimed, Davis said.
The federal Bureau of Alcohol, Tobacco, Firearms and Explosives is tracing the weapons to try to determine how they were obtained by the suspects.
It was not clear what charges Tsarnaev would face. The twin bombings killed three people and wounded more than 180.
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.