New Orleans — New Orleans Police Superintendent Ronal Serpas was almost giddy on Thursday as he announced arrests in four different local homicides, and he stressed that the city is making definite progress in its fight against violent crime.

Serpas lavishly praised investigators and commanders in the city’s Homicide Division for the arrests, all of which came in the past 24 hours. Police also solved another homicide by “exception,” which means investigators identified a suspect who is already dead.

Police booked Devante Billy, 18, Kermitt Bernhart, 20, Dwayne Butler, 24, and Chevroun Smith, 21, with second-degree murder in four unrelated slayings. Albert Reed was the deceased suspect who was tied to the 2004 killing of Aaron Morgan, 29, on Forstall Street in New Orleans.

Serpas said the arrests bolster his belief that New Orleans police are getting a handle on the city’s persistent crime problem. Serpas said all of the arrests were the result of excellent and dedicated police work, along with a growing level of cooperation from local residents.

“I can’t tell you of how proud I continue to be of the Police Department and the homicide department,” Serpas said. “We are turning the corner slowly but surely.”

One of the arrests was in the recent slaying of college student Valan May in eastern New Orleans. Police had already arrested a teenager in that case but were searching for an accomplice they say was also in the car when May was killed.

Lt. Gary Marchese, the homicide commander, said that through canvassing the neighborhood officers were able to identify Devante Billy as that suspect. Billy was arrested at a relatives’ home in the 7400 block of Weaver Street on Thursday morning. Marchese said police have not tied down a motive in the shooting but said early indications are that May, a budding artist, did not know either assailant.

Police also arrested Chevroun Smith and Kermitt Bernhart on Thursday morning. Smith was arrested in the murder of Ali Robinson at Stallings Playground on April 13. Bernhart is accused of killing Christopher Lambert on Oct. 19. Lambert was found dead in an abandoned home in the 2400 block of Orleans Avenue. Bernhart was arrested after Eighth District officers investigated complaints of loitering in front of a Royal Street business. Officials say Bernhart discussed Lambert’s killing before it happened and was picked out of a photo lineup.

In one of the two older cases, Dwayne Butler was booked with the 2006 killing of Keith Simmons, 17, in the 700 block of St. Charles Avenue. In that case Butler was already paroled for a conviction for being an accessory after the fact to second-degree murder. When he learned about a warrant for his arrest in the Simmons killing, he turned himself in to his parole officer, according to police.

Serpas said that all of the men arrested had lengthy arrest records and were well known by police. Some of the men had prior arrests for murder, manslaughter, robbery and other violent crimes. Serpas said that verifies what his department has already discovered from studying the recently reduced statistics from the FBI on crime in the United States.

New Orleans may have the nation’s highest homicide rate, but its violent crime rate is lower than the national average for cities near its size, Serpas said. More importantly, the city’s arrest rate for violent crimes is 21 percent higher, a sign that New Orleans police are locating the criminals, Serpas said. However, he said that criminals are receiving too many “breaks” from the court system, a situation Serpas found unacceptable.

“Each and every victim gets no break,” Serpas said. “Our department is arresting violent offenders; we are bringing them to court.”

He said that as police work harder, the public gains confidence in their work. Calls for service in the city are increasing every year, and Serpas said that means residents believe reporting crime will get results. The more information detectives gather on all crime, the better they can do their jobs, he said.

“The more people who are reporting crimes, the smarter our detectives can be,” Serpas said. “All this comes together very nicely, very tightly.”

Serpas also said he was pleased to note a steep drop in crime in the French Quarter and Central Business District during Halloween, with no violent crimes being reported a year after there was a homicide and multiple shootings during the celebration. Violence across the city was down, with only one shooting reported on St. Bernard Avenue on Wednesday night and a homicide related to a domestic dispute that morning.