Boise police are improving on their record of clearing serious crime cases.

The Boise Police Department reported it cleared 38 percent of all serious crimes reported in 1989, a 36 percent increase compared with the number of serious crimes solved a year earlier.Crimes categorized as serious are murder, rape, robbery, aggravated assault, burglary, theft, vehicle theft and arson.

"We're trying to work smarter, not just harder," said Boise Police Lt. Larry Jones, who heads the detective division. "Our investigators are better trained, and we're focusing on the criminals who are hurting us the most."

The department solved 28 percent of such crimes in 1988.

A crime has been solved when police say it is "cleared." Cleared means an arrest was made in connection with the case, investigators named a suspect but prosecutors declined to prosecute or the victim declined to press charges.

It also includes cases police determined to be unfounded, a matter that should not be handled by law enforcement or a matter in which a suspect was named but died or fled jurisdiction.

"It means the cases were investigated to a conclusion. At that point, we have done everything possible for law enforcement - we've built the case, and now it's in somebody else's ballpark," Jones said.

Jones said such programs as school resource officers, Boise's inherently low crime rate and efforts to focus on chronic juvenile and adult offenders contributed to the increase in cases cleared.

"I'd like to take credit for the increase, but I can't. It may be just pure dumb luck," Police Chief James Carvino said.

He said the increase in cases solved may be due to more sophisticated training given to officers and detectives, a more informed public and such programs as victim-witness coordinators, who assist victims, especially children, through the court process.

From 1984 to 1989, the department cleared about 27 percent of all serious crimes.

Since 1984 the department has cleared almost 60 percent of murders, 75 percent of aggravated assaults and about half of all reported rapes and robberies.

But non-violent crimes show lower rates. Since 1984 less than 13 percent of burglaries, about 17 percent of arsons, 22 percent of vehicle thefts and 29 percent of other thefts had been cleared.