Crime dropped significantly in the five neighborhoods Prince George’s County police targeted in a special anti-violence initiative this summer, at least partly because the most dangerous criminals heeded officials’ direct appeals to stay out of trouble, authorities said Wednesday.

None of the 67 violent criminals forced to come in for face-to-face meetings with law enforcement officials and community activists as part of the crime prevention effort was arrested again over the summer — at least not in Prince George’s, authorities said. They said the criminals, who lived in the five neighborhoods police had identified as “focus areas,” must have taken to heart the message that police were watching them closely and that it was time to seek help from social services.

“I’m sure it had some impact,” Prince George’s Police Chief Mark Magaw said after a news conference Wednesday. “I know some took advantage of the services.”

Glassmanor, one of the five focus areas, had 12 percent less crime from May 22 to Sept. 1 compared to the same period last year, police said. In Suitland, another focus area, crime dropped 9.7 percent, police said. In Hillcrest Heights, another focus area, crime was down 23.2 percent, police said. In Riverdale and Langley Park, crime dropped more than 22 percent, police said.

Police officials said they think the face-to-face meetings with violent offenders played some role in those drops, even if they could not precisely quantify the impact. The criminals forced to come to meetings by their parole and probation agents had serious convictions, such as carjacking and murder. That none of the 67 got in trouble again was notable, police said.

“The absence of that data, in my opinion, is a good thing,” said Assistant Chief Kevin Davis, who spearheaded the initiative. “Perhaps the message did get through.”

Davis said there were three homicides in focus areas during the initiative, stemming from two domestic disputes. Police have made arrests in both cases, he said.

Crime also did not seem to move from the focus areas to other parts of the county, police said. Overall, police said, crime is down 9 percent this year in Prince George’s County over the same period last year. Violent crime, police said, is down 12.1 percent, and property crime dropped 8.4 percent.

“We all can be proud of these numbers,” Magaw said.

Still, homicides remain a problem in the county. As of Wednesday, Prince George’s had 85 homicides, including justified killings and fatal police shootings, compared to 76 over the same period last year. Magaw said that much of the increase is from an unusually violent January, when the county had 16 homicides, and that killings have decreased since then. Still, he said, he was “not satisfied” that killings had increased, even if other crime continued to drop.