An August double murder-suicide in the Valencia Bridgeport community skewed the year-to-date homicide rate for a valley that typically sees less than a handful of murders all year. But the Santa Clarita Valley’s overall reports of serious and violent crimes fell 15.81 percent through August, compared to the same period in 2010.

Violent and serious or “Part 1” crimes include homicide, forcible rape, robbery, aggravated assault, burglary, larceny, grand theft auto and arson.

All categories were down through August with the exception of arson crimes, according to figures released this week by the Los Angeles County Sheriff’s Department.

The number of reported Part 1 crimes fell more dramatically in county unincorporated areas of the SCV (down 20.9 percent) than in the city (down 13.7 percent).

The murder of an elderly couple Aug. 5 in Valencia brought the valley’s year-to-date murder total to three. That’s a statistical increase of 57.14 percent over the two murders reported through August 2010, one each in the city and the unincorporated area.

The two murders in Bridgeport were the city’s only murders of 2011, double the number reported in the city through August 2010 for a statistical increase of 83.3 percent. The unincorporated murder rate remained unchanged, with one each through August 2010 and August 2011.

Forcible rape fell 48.8 percent in the unincorporated SCV through August with two victims, and by 35.4 percent in the city with 11 victims.

Reported robberies fell by 32.9 percent valley-wide through August, thanks to a drop of 42.3 percent in the city. Robberies increased 10.8 percent in unincorporated SCV areas.

Aggravated assaults were down 52.7 percent in the unincorporated areas and 32.5 percent in the city.

The number of burglaries in the unincorporated SCV fell by 14.5 percent with 189 incidents through Aug. 31, and by 6.7 percent in the city (361 incidents).

Larceny (theft) fell by 15.9 percent in the unincorporated SCV and by 10.9 percent in the city.

Grand theft auto fell by 41.9 percent in the unincorporated SCV with 50 incidents so far in 2011, and by 19.3 percent in the city (151 incidents).

Arson increased by 36.8 percent in the unincorporated areas with 11 incidents versus eight, and by 29.9 percent in the city with 17 incidents versus 13.

Percentages are calculated by the Sheriff’s Department.