Calgary's rapid growth and rising affluence might be partly to blame for its latest spike in violent crime, a local criminologist says.

Nine people have been killed in the past eight days — four over the weekend alone — in incidents ranging from a gang-related shooting, to a hit and run and a double slaying. In another incident, a 17-year-old boy was killed last week when he was pushed into the path of a C-Train.

The violence was capped on Sunday when the partially clothed body of a woman was found in the downtown Ramsey neighbourhood early that morning. Police said some residents had heard the woman cry for help, but did nothing about it.

"This seems to be typical characteristics of a strictly urban society where people become impersonal, when society has become impersonalized, where people don't care what happens to their next-door neighbours," said Mahfooz Kanwar, a criminology and sociology professor at Mount Royal College.

Calgary police called officers back from their vacations to help deal with the violence.

Kanwar said such a rise in violence is expected to happen in a growing city such as Calgary, which welcomes thousands of new residents every year.

"People are here and people don't know each other. They have left their roots somewhere else," he said. "And especially when you have money, you don't depend on anybody. You don't worry about anybody. It's sad that we don't."

None of the recent crimes has been linked, and police continue to investigate all cases.

One man died in a gang-related shootout downtown on Sunday. Two other people were shot and injured in separate incidents reported over the weekend.

Last week saw two non-fatal shootings and the discovery of human remains in the city, as well as the death of Gage Jeffery Prevost, 17, who was pushed in front of a C-Train at a downtown transit station on Aug. 1.

Police confirmed he was likely pushed and slipped into the gap between two train cars. He died instantly of massive internal injuries.

At a memorial for Prevost on Aug. 3, members of the crowd chased a woman they thought fit the description of a suspect police were looking for, but police and C-Train security intervened. Police interviewed the woman and later said it was a case of mistaken identity.

Spike in crimes of 'great concern'

Acting police Chief Peter Davison said Sunday that Calgary is still a safe place to live, but he acknowledged the latest run of serious crimes is worrisome.

"The events of the past two weeks have certainly caused us great concern. We've called a number of investigators back from their holidays," Davison said.

"We've seen these types of spikes before, and we'll see them again. This certainly isn't the most number of homicides we've seen in this period of time," he added, noting a couple of spikes in homicides in the early- to mid-1980s.

Part of the problem, he said, is a shortage of police officers.

"We've had difficulties recruiting people and attracting people to policing, not only in Calgary, but … right across the province," he said.

"We're competing with a very hot economy and we continue to strive to make efforts to get more people into the seats and get more officers onto the streets."

Woman's screams unheeded

Police also expressed concern over the lack of response by residents in the Ramsey-area homicide.

They said the woman, thought to be in her 20s, was the victim of what appeared to be a sexually motivated attack. But residents who heard the woman's screams did not call police, they said.

"The information we have is that someone heard the woman crying and screaming, and didn't contact us," Staff Sgt. Keith Cain of the Calgary Police Service's major crimes section said Sunday.

"Certainly it's a concern … difficult to explain why that may have happened. It certainly may have been an assumption on that person's part that someone else would call it in, or they did not want to get involved."

Police have urged the public to call them immediately when they hear or see anything suspicious, rather than assume that someone else has already done so.