The Prince George’s County Police Department is ramping up officer patrols after the jurisdiction just outside the District tallied 12 homicides in the first 11 days of July.

Officers began working 12-hour shifts starting at noon Tuesday, an increase from the typical eight- or 10-hour shift, with extra patrols focused on areas where there has been an uptick in violence.

Many of the recent homicides stem from people using guns to settle disputes, said Police Chief Henry P. Stawinski III, addressing the media Tuesday evening. This year’s homicide count stood at 49 as of midday Tuesday, one fewer than at the same time last year.

“This is my home, and it troubles me when we have these events, but more troubling than that is the frequency with which these disputes are devolving into violence,” Stawinski said.

The department hopes the heightened police presence will make people think twice about pulling the trigger in a heated moment. “We can’t predict what is going through someone’s mind when they decide to get that angry to pull out a gun and shoot,” police spokeswoman Jennifer Donelan said.

Mapping homicides in the District and the surrounding suburbs since 2000.

Stawinski declined to say how much the increased enforcement will cost, saying he has the confidence of county leadership to manage his budget. He said he would offer a total at the end of the initiative.

John “Zeek” Teletchea, president of the police union that represents officers in Prince George’s, said officers will be working overtime to meet the new scheduling.

“Even though it’s sad that we’re in this position, we are going to do our job,” Teletchea said. “It highlights the need for additional police officers.”

The department has about 1,650 sworn officers, although there should be about 1,850 to be a full complement, Teletchea said.

The last time the department saw such a surge of violence was near the start of County Executive Rushern L. Baker III’s first term in office, in January 2011, when police investigated 13 homicides in 12 days. County police didn’t move to 12-hour shifts then but used other methods to increase patrols, Stawinski said. The string in 2011 involved more retaliatory slayings, he said.

“County Executive Baker has the utmost confidence in Chief Stawinski’s approach to stem the recent spate of violence in the County,” Baker spokesman Scott Peterson said in a statement.

The homicides that Prince George’s County police are investigating this month include two double fatal shootings. County police have announced arrests in at least two homicides, and some cases are being investigated as possible self-defense shootings.

The causes behind some of the recent shootings range from anger about having to wait too long in a line to long-running interpersonal disputes, Donelan said. “We need people to calm down, take a breath and walk away,” she said.

Along with those cases have been high-profile killings.

Over the weekend, police arrested Navar Beverly, 38, in the strangulation of his stepfather, Richard Pinkney, 65. Beverly killed Pinkney and then posted a photo of himself on Twitter next to his stepfather’s body, police said.

On July 1, Adriano Lombre, 55, was fatally shot on the outer loop of the Capital Beltway. Police have pleaded with the public to come forward with information in the death of the “innocent victim”; no 911 call came in to report the shooting along the busy highway.

Stawinski said the shifts are not “zero tolerance” policing but a “measured” response to keep crime low. Overall violent crime is down 1 percent this year.

“I’m confident that this will make a difference,” Stawinski said.