Shock, grief and anger dominated a prayer vigil for a baby, a toddler and their mothers who were shot to death while the women held their children in their arms.

City leaders who spoke at the vigil at a neighborhood church, attended by about 100 people, summed up the crime with one word: Evil.

"How does evil like this exist in our city?" Mayor Greg Ballard said. He urged people to channel their outrage into community policing, neighborhood associations and other steps to make the community safer.

"It's easy to be heartbroken, and you should be. But you should be angry, and I'm angry," Ballard said.

All four victims were shot repeatedly late Monday, said Indianapolis Assistant Police Chief Eva Talley-Sanders. All died at the house on the city's north side except for 4-month-old Charlii Yarrell, who died at a hospital.

The other victims were Jordan Hunt, 23 months; his mother, Gina Hunt, 24; and Charlii's mother, Andrea Yarrell, 24.

Police Chief Michael Spears, who spoke at the vigil, called the killings "an act of inexplicable evil."

Relatives of the victims turned on four electric candles that are to remain lit until the killers are caught. Police said they had identified people they wish to question and were looking for them, but they would not name the people or describe them.

"There is no reason whatsoever for this hideous thing to happen. I promise you we're not going to stop until we find out who did this, until we put the dogs in the cage," Marion County Sheriff Frank Anderson said.

"We're killing each other. When we start killing babies, that's enough."

Two handguns were found within a block of the house, where all four of those killed lived, said Sgt. Matthew Mount, a police spokesman.

Annie Boyd, the mother of Andrea Yarrell's boyfriend, told The Indianapolis Star that her son heard a gunshot while he was on the phone with Yarrell.

Gene Boyd, who is in the Indianapolis Men's Work Release Center on charges in a drug case, told his mother he heard someone break into the home.

"He heard the shot, then heard Gina holler out: 'Those are my babies!"' Annie Boyd said. "After that the phone went dead."

Gene Boyd then called his mother, who called 911.

A set of scales, several weapons, a safe and one pound of a what is believed to be marijuana were found in the house, Talley-Sanders said. She said police had been called to the home three times in 2007 to investigate reports of armed robbery, burglary of a resident and a stolen vehicle.

"There's just a number of factors that have to be looked at," Mount said. "Because of the things that were found at the scene they are going to look at every possible motive."

Yellow crime scene tape cordoned off nearly a half block of the street, lined with modest brick and frame houses. At the small one-story white house where the slayings occurred, the front entrance was flanked by signs reading "Peace on the streets, stop the violence," and stuffed animals were piled on the steps and the bushes.

"It's not shock, because it's reality. It's something that happens every day," said Kiyanna Sampson, a cousin of victim Gina Hunt. "It's really sad that somebody would take innocent lives like that. It almost makes you think, What are people possessed with? What are they thinking? What type of drugs are they on?"