When a Philadelphia police officer responds to a domestic violence call, the officer probably does not know if the home has a history of problems or whether someone living there has an active restraining order.

If there are no obvious signs of violence, the officer typically can do nothing more than leave a business card with hotline numbers.

And if no police action is taken, the initial report the officer files - known as a "48" - often says simply "domestic violence, adjusted by police."

But after an unexpected surge in domestic homicides this year, the Philadelphia Police Department is rewriting the book on the way officers investigate, report, and make referrals in domestic abuse cases.

Last year, there were 21 domestic homicides. As of Dec. 11, there had been 35 - a 67 percent increase. Since then, there have been two more homicides that eventually could be classified as domestic.

This jump comes with incongruous timing - the city's overall homicide rate has dropped 23 percent in the past two years. As of yesterday, the city had logged 300 homicides, compared to 390 in 2007.

While domestic violence is impossible to eradicate, police leaders believe the changes they are planning will make officers more effective in dealing with the problem and getting help to victims.

An updated police directive will not be ready until after the new year, but the focus will be on better collection and use of information.

Police districts will be required to keep their own databases on domestic calls, by name and address, which will show victims and homes with repeat calls.

Dispatchers will be required to provide that data when an officer responds to a call, and to report whether anyone in the home has obtained a protection-from-abuse order from the courts.

"The point we wanted to make is there are warning signs," said Deputy Commissioner Patricia Giorgio-Fox. "We're looking for good predictors for future violence."

There were warning signs in several of this year's homicides.

Since January 2008, police had fielded 10 calls from the North Philadelphia home of Willie Lamont Scott, three of which were classified as domestic calls. On Feb. 21, Scott fired more than 10 shots into his ex-girlfriend, Larosa Gonzalez, in front of the couple's 4-year-old daughter, police said.

Police received 21 calls from the home of Renee Farrow-Nesmith, seven of which were related to domestic violence. In June, her husband, Marvin Nesmith, shot her and another woman during a Father's Day celebration at their Overbrook home, according to police.

Twenty-one of this year's domestic homicide victims had made 178 previous calls to 911 since January 2008. A further 94 calls were made from the alleged perpetrators' homes.

There is no way to know whether the coming changes at the Police Department could have prevented any of this year's homicides.

And several of the victims had taken necessary precautions - two had obtained protection-from-abuse orders. Angela Atkinson, of Somerton, was one of them. Despite the order, her estranged husband, Edward Atkinson, shot her and killed himself in October, police said.

Several other victims were receiving services from Women Against Abuse, which operates a hotline and the city's only domestic abuse shelter, when they were killed, said Heather Keafer, the group's development director.

Still, said Giorgio-Fox, who is spearheading the changes to the domestic violence directives, police can do a better job of domestic violence "triage" and of ensuring that the most troubled homes get the necessary services.

One anticipated change would require officers to fill out more complete reports. Giorgio-Fox wants those reports to include information such as the nature of the disturbance and whether force or the threat of force was involved.

Giorgio-Fox, who piloted the city's first domestic violence unit in the early 1990s, said the department was working on a checklist so officers would not be encumbered by additional paperwork.

The information they gather would let domestic violence detectives classify the seriousness of the call and decide whether follow-up is warranted.

Each of the six detective districts now sets its own practices for domestic cases. Giorgio-Fox said standard practices would be adopted, though the details have not been ironed out.

"We need to be smarter about how we make referrals and what we expect of our partners," she said.

To that end, police leaders went to the Domestic Violence Law Enforcement Committee earlier this year to discuss the increase in homicides.

The committee, which grew out of a task force formed during the administration of Mayor John F. Street, is charged with improving services to domestic violence victims.

Police officials plan to discuss the changes with the committee and to talk about how they can use the police data to intervene in domestic cases.

"Without some kind of intervention, it's not going to get better," Giorgio-Fox said. "It's like alcoholism. . . . It becomes part of the fabric of the relationship."

She said the department needs strong partnerships with domestic violence agencies so officers can make targeted referrals.

"I need for officers to have some avenue to do more than just hand out a card," she said.

Carol Tracy, the executive director of the Women's Law Project, cochairs the domestic violence committee. She said creating the kind of partnership Giorgio-Fox wants was "critical."

"The referral capacity is there, but they're stretched," she said.

Four main agencies deal with domestic violence in the city: Women Against Abuse, Women in Transition, Congreso de Latinos Unidos, and Lutheran Settlement House.

"Maybe this crisis will bring us all together to have a more comprehensive strategy for how we're going to deal with domestic violence in Philadelphia," Tracy said.

Domestic violence is not limited to romantic partners - it includes anyone living together as a family, such as brothers and sisters, children and parents.

This year's homicides included two sons who killed their fathers and a daughter who killed her mother. Two fathers killed their children.

Several other large cities use similar databases to track and respond to domestic violence, and Police Commissioner Charles H. Ramsey has focused on domestic violence at two previous jobs.

Ramsey led a project to reduce recidivism among abusers when he was with the Chicago police and, as chief in Washington, he employed data in some of the same ways as planned for Philadelphia.

Statistics kept by police and other agencies show a jump in domestic violence overall this year.

In 2008, Philadelphia police received more than 89,000 domestic calls. In first six months of this year, the last period for which figures are available, police responded to 59,600 calls.

Keafer and Tracy both said the downturn in the economy could be driving up domestic violence, but they could not be sure that was the only cause.

"We're doing everything else the same way," Keafer said. "The only variable that seems to have shifted is the economy. That seems to be the best educated guess."

Women Against Abuse also has seen a jump in hotline calls, and the agency's shelter has been forced to deny twice as many people entrance this year.

"Every time a hotline counselor has to turn someone away, it's a heartbreaking experience," Keafer said. "The thing that really drives us crazy is that domestic violence is preventable."

Said Giorgio-Fox: "We need to feel comfortable at the end of the day that we did and they did everything we can. At the end of the day, we will still have failures, but not because we haven't done everything we can."

Contact staff writer Troy Graham at 215-854-2730 or tgraham@phillynews.com.