Boston's homicide count last year not only hit a 10-year high, but also took one of the biggest jumps for a city of its size, a Globe review found.
Boston's death toll increased by 17 percent to 75, the sixth-highest percentage increase among 15 cities with comparable populations surveyed.
The number of killings fell last year in five of the similarly sized cities, and also in the nation's largest cities -- New York, Los Angeles, and Chicago.
Even with last year's increase, Boston's homicide rate per person falls in the middle of the pack of cities with estimated populations between 500,000 and 700,000, the Globe's review found.
About 13 people per 100,000 residents were homicide victims last year in Boston, a rate higher than cities such as Austin, Seattle, and Portland, but lower than cities such as Washington, D.C., and Baltimore, where 42 people per 100,000 residents were slain last year.
Mayor Thomas M. Menino, who started his fourth term last week and has been stung by criticism that he is not doing enough to fight violent crime, said Boston is one of many cities struggling with a surge in killings.
''There are a lot of communities out there facing similar challenges," Police Commissioner Kathleen M. O'Toole agreed.
Menino said he would like to add hundreds of officers to the Boston police patrol force, but that the cost is prohibitive.
The 300 or more additional officers proposed by some, including last week by City Council President Michael F. Flaherty, would cost the city at least $21 million a year, Menino said.
Although recent classes that have graduated from the Police Academy have replenished the ranks, the patrol force is down about 75 people since mid-2000, to about 1,400.
The mayor blamed the spike in homicides on the increase in the population of young males in the city, and the simultaneous decline in federal and state assistance.
''When I came into office, they told me that in eight to 10 years a bubble of adolescents would come on the scene," he said in an interview. ''It's happening now at the same time our [youth outreach] programs are being cut."
There is some evidence for the mayor's assertions. Of the 75 homicide victims last year in Boston, 37 were men between the age of 15 and 24. Through the first 10 months last year, those 24 and under accounted for two-thirds of all firearm-related arrests, according to police statistics.
While the city's overall population grew by less than 3 percent between 1990 and 2000, the number of males under 18 increased by nearly 8 percent, according to a Boston Redevelopment Authority report compiled from Census data.
Nationally, young males age 18 to 24 are disproportionately involved in homicides, either as victims or perpetrators, the US Justice Department said.
In some cities where homicides declined last year, officials credit innovations in how they fight crime, not how many patrol officers they have. Chicago officials, for instance, said they have installed surveillance cameras in high-crime areas and Baltimore detectives have sharpened their focus on repeat offenders.
''We have established lists in all of our police districts of those repeat violent offenders who have been causing us the most trouble and we've gone after them," said Matt Jablow, a police spokesman in Baltimore, where the homicide count dropped about 3 percent last year. In other cities where homicides went down, however, officials said they could not pinpoint a reason.
''You can't tie it to staffing levels, you can't tie it into anything like that," said Officer Catherine Kent, police spokeswoman in Portland, where homicides fell to 22 in 2005 from 28 in 2004. ''It's just an unpredictable crime."
The difficulty of establishing why homicides are increasing in some cities and dropping in others, specialists say, underscores the challenges facing cities such as Boston, Milwaukee, and Memphis in trying to reverse double-digit percentage increases in homicides.
Professor Alfred Blumstein, a criminologist at Carnegie Mellon University in Pittsburgh, said that compared with a decade ago, when violent crime was plummeting across the country, the national trend is now mixed.
Blumstein said the surge in violent crime has been fueled in some places by ''a greater willingness to use extreme violence," especially among young people.
David Kennedy, director of the Center for Crime Prevention and Control at John Jay College of Criminal Justice in New York, said it often takes one killing to set off a series in cities like Boston plagued by gangs. As a result, homicide rates can spiral out of control quickly.
''The streets in this hard-core population we're talking about are a tinderbox and it can take very little to set them ablaze," he said.
Police have blamed the uptick in Boston on more teenage males on the streets, a wider availability of guns, a culture of retaliation, and a lagging economy, among other reasons, but Kennedy said the reasons for an increase be much more visceral.
''It's respect, it's boy-girl, it's back-and-forth vendettas," he said.
In Milwaukee, where homicides increased by 38 percent to 122 last year, officials have impaneled a commission to investigate what's fueling the increase there.
''We have no identifiable trend we can point to," said Lieutenant William Jessup. ''We started a homicide review commission comprised of various agencies to help us determine what the root causes are."
El Paso had an increase of three homicides in 2005 to 14, but with 2.4 homicides per 100,000 people it boasts the lowest rate of cities close in size to Boston.
Lieutenant Alfred Lowe credited a strengthened homicide unit and more attention to specific types of murders.
In the early 1990s, for example, most homicides in the border city were gang-related drive-by shootings.
The department responded by creating teams to focus on solving drive-by killings, Lowe said.