"We rolled out like a small army," said Hogan, who sent detectives from his office to coordinate with local police. But two more homicides would occur in the next five days, one in the city limits, the other just outside.
"You get all your guys out there one night, you've just gotten your feet back underneath you, and then another call comes in," he said.
For Hogan, who had taken office just months before, that was the last straw.
Since late summer, Hogan and county detectives have been conducting a series of raids and arrests in Coatesville designed to cut down on violent crime by targeting those they view as most likely to commit it.
Hogan calls it "Operation Silent Night," and, he said, it's working. Only one murder has been reported in the city since the operation began in earnest.
"We had been building up to it," Hogan said, but after the July homicides, "there couldn't be any more preparation."
Hogan and his detectives, with help from Coatesville police, have made about 35 Silent Night arrests, targeting known criminals with a history of violent offenses and pending drug or firearms warrants.
Sometimes, that has meant taking out the leader of a local gang. Other times, it has meant demonstrating force, such as raiding suspected drug dens with SWAT teams.
"You need to think, what's the pressure point? Who's the weakest guy in the crew?" Hogan said. "It's about bringing pressure day after day."
Coatesville has become the epicenter of violent crime in Chester County. Of the 10 homicides in the county in 2012, six happened in Coatesville. In 2012, Philadelphia's murder rate was 18.6 per 100,000 residents. In Coatesville, with a population of a bit more than 13,000, the murder rate was 45.7.
Much of the violence, Hogan said, is drug-related.
Coatesville police, who have dealt with staff cuts and changes in leadership the last few years, say that Silent Night has helped, but that more manpower is crucial. Police provided intelligence and leads for the district attorney's investigations.
Coatesville Detective Sgt. Brandon Harris said the department needed help from other agencies, especially since its full-time drug unit was dismantled.
"When one person gets locked up for selling, the next person takes over," Harris said. "You lock up 10 big drug dealers and the next day, you have the low-level drug dealers stepping up and taking over. It's never going to stop."
Still, Harris said, Silent Night has helped Coatesville get dealers off the streets.
A similar operation in neighboring Delaware County has yielded some success, said District Attorney Jack Whelan. He said targeting criminals with active warrants, particularly in high-crime areas such as Chester City, is "always useful."
John R. Merrick, Chester County's public defender, said identifying a propensity for violent crime could be tricky.
"We routinely are on the receiving end of periodic drug sweeps, and they seem to be effective as far as they produce arrests," Merrick said. "As far as predicting when or if somebody is going to commit a crime, I think we will leave that up to higher powers."
Arrests alone, however, aren't enough, Hogan acknowledged.
"We can't arrest the problem away in Coatesville," he said. Safety isn't the only issue in Coatesville; economic growth in one of the county's highest-taxed communities is a key to revitalizing the city.
Hogan said he is pleased with the program's progress so far. When asked why he decided to call the operation Silent Night, he smiled.
"We'd been hearing over and over again from the good citizens of Coatesville, 'I can't sleep at night,' 'I hear gunshots and screaming.' "
Said Hogan: "We wanted to give them one silent night."
Contact Aubrey Whelan at 610-313-8112 or firstname.lastname@example.org, or follow on Twitter at @aubreyjwhelan.