A sharp increase in one area of crime has left St. Joseph Police Department officers scratching their heads.

The number of aggravated assaults has more than doubled since this time last year, according to police statistics.

An aggravated assault involves serious harm or permanent injury and sometimes will involve a weapon, while a simple assault lacks serious harm.

The part that has really stumped the department is that while the number of aggravated assaults has risen, the number of simple assaults have gone in the other direction.

“It’s surprising that while the aggravated assaults are up, the simple assaults are down, and that’s one that I don’t know an explanation for right now,” Police Chief Chris Connally said.

Simple assault cases are down to 825 from 904 during this time last year.

One contributing factor to the increase in aggravated assaults is the number of domestic, or family related, cases. That number has contributed to 70 percent of the increase in overall aggravated assaults since 2007.

Mr. Connally speculated that tougher economic situations have placed increased strains on domestic relationships, perhaps leading to the increase in domestic assaults.

A year-to-date evaluation of aggravated assaults shows 89 cases through August 2006 and 71 cases through August 2007. This year, there have been 149.

The only month that saw a decrease in cases was March, down four cases from March 2007.

The day of the week and hour of the day also show some trends when calculating the overall number of aggravated assault cases in the area.

The majority of assault crimes occur between 3 and 6 p.m. and after 9 p.m.

Sunday, Thursday and Saturday — in that order — prove to be the days on which the most assaults are committed.

While the changing demographics of St. Joseph do not appear to play a role in the increase of aggravated assaults, Mr. Connally says further analysis will need to be considered to determine a cause.

“That’s one of the real challenges when you’re dealing with aggravated assault, because the increase in this particular case is domestic related, and because it’s a more response-driven crime, it’s a little more challenging to deal with the increase,” Mr. Connally said.

While cases of burglary or larceny can more easily be deterred through programs such as neighborhood watch or traditional crime prevention approaches, Mr. Connally says it isn’t so easy with assault cases.

“Some of the things we probably need to look more closely at are our support services and getting them more actively involved,” Mr. Connally said.

Megan Tilk can be reached

at megantilk@npgco.com.