BOSTON - Neighbors gathered around a chalk rainbow on a sidewalk outside 8-year-old Martin Richard's home while friends of Krystle Campbell, 29, posted notes on Facebook, all grieving for two of the people killed in Monday's bombing at the Boston Marathon.

The third victim, a Boston University graduate student killed while watching the race with friends near the finish line has not been identified by name, pending permission from the family.

A Little League baseball player, Martin lived in the blue Victorian house in working-class Dorchester - a Boston neighborhood dotted with "Kids at Play" traffic signs and budding trees - with his parents Bill and Denise, sister Jane, 7, and brother Henry, 10.

Martin Richard, who was killed in the Boston Marathon attacks, is shown in this undated family handout photo released on April 16, 2013. [Photo/Agencies]

"Very happy, happy-go-lucky," said Jane Sherman. Martin was afraid of her dog, a Rottweiler, she said, but he always gave her a cheerful greeting. "An outgoing, wonderful kid. This is a horrendous loss."

Bill Richard told the world in an email on Tuesday that his son had been killed when bombs exploded at the marathon finish line. Martin's mother and sister were seriously injured.

"My dear son Martin has died from injuries sustained in the attack on Boston," Bill Richard wrote. "My wife and daughter are both recovering from serious injuries. We thank our family and friends, those we know and those we have never met, for their thoughts and prayers."

The family released a photo of Martin at a hockey game, dressed in Boston Bruins regalia.

Campbell's friends remembered her outsized personality, passion for the Boston Red Sox baseball team, and the way she belted out Eminem and Rihanna's "Love the Way You Lie" every time she heard it on the radio.

"I am shocked, stunned, and besides myself," one friend wrote on Facebook. "You will be missed Krystle Campbell, but your big smile and twinkling blue eyes will live forever in our hearts and minds."

Krystle M. Campbell, 29, who was killed in the Boston Marathon attacks, is shown in this undated family handout photo from her Facebook released on April 16, 2013. [Photo/Agencies]

Along with the three people killed on Monday, at least 180 people were injured.

Michael McGlynn, mayor of Medford, Massachusetts, where Campbell grew up, said he confirmed her death with her father, William. "Mr. Campbell said that she certainly was a dream daughter, the daughter that every father dreams to have, and friends of hers said that she was eager about life," he said.

"She had a great sense of humor and freckles and red hair that brought her right to her Irish roots. She was someone who worked hard at everything she did."

"Another friend said she may have been a little loud at times but it was a loudness you loved," McGlynn said.

A wish for "Peace" written in chalk marked a memorial outside Martin's home. Drivers slowed as they approached it, paused, and made the sign of the cross.

Another neighbor, John Do, placed flowers there. A veteran of Vietnam's navy, he said the attack on the marathon was "even worse than what I saw on the battlefield - to do this to children - horrible." Do left in tears.

Marchell "Tiny" Watson and Margaret Admirand recalled the Richard children playing soccer and hockey on the lawn, chalking the sidewalk with rainbows and butterflies, and dressing in costumes for Halloween. "Can't you just see them up there kicking the ball on the lawn?" Watson asked.

"And their little sister running after them," Admirand said.

Watson said that for years Denise Richard had jogged up the hill, pushing her boys in a stroller, to bring Henry to school.

Martin, who recently celebrated his First Communion, had played flag football and was a member of the Savin Hill Little League team, neighbors said. Opening Day for the league was scheduled for next week. Savin Hill Little League president Tony King said Martin was "a very, very much loved little kid."

At Summer Shack, where Campbell had been a manager, she was known as a hard worker who devoted summers to the restaurant's food stands on islands in Boston Harbor. She took another food industry job several months ago for greater opportunities, said Stephanie Guerrier, who worked with Campbell at Summer Shack.

"She was honestly the most amazing person I've ever met," Guerrier said. "I'm not saying that because she's just passed. That's what she really was."

"Everybody that knew her loved her," Campbell's mother, Patty, said choking back tears during a news conference "She was always smiling. You couldn't ask for a better daughter."

"I can't believe this has happened," she added. "This doesn't make any sense."