Boston ? The execution-style slayings of four young men in a basement music studio this week cast a spotlight on a crime wave that has pushed murder in Boston to a 10-year high.

While the murder rate nationally has dropped over the past decade, some cities – such as Boston and Philadelphia – are seeing it spike. In Boston, the number of slayings has more than doubled in the past several years, climbing from 31 in 1999 to 71 so far this year.

Criminologists blame the increase in part on a decrease in funding for neighborhood policing because of the war on terrorism; a demographic bubble of teenagers and young adults; and the scaling back since the late 1990s of after-school and anti-gang programs, such as midnight basketball, summer jobs programs, counseling and high school equivalency diploma courses.

“The great successes we had a decade ago are gone. We let down our guard,” said James Alan Fox, a professor of criminal justice at Northeastern University and author of five books on violence and homicide. Police blame the rise in murders in Boston on guns and gangs.

In Philadelphia, there have been 365 homicides so far this year – up from 330 in 2004. Baltimore has seen 259 killings, which is down from 276 in 2004, but up from 253 in 2002.

In some larger cities, the murder rate continues to drop. New York’s and Chicago’s rates have plummeted to 1960s levels – New York had 508 killings through Dec. 11, a drop of about 6 percent from last year; Chicago’s toll is slightly below last year’s 445 homicides for the year, but far from the 600 recorded in 2003. Los Angeles had 474 through Thursday, down from 498 during the same period last year.