Most instant news from the District’s crime scenes now will run through a city website. (Amanda Voisard/For The Washington Post)

For years, D.C. residents who wanted nearly instant reports about serious crimes in their neighborhoods could turn to the police department’s official Twitter account. Shootings, robberies and purse snatchings scrolled by.

The department has now decided to take most crime alerts off Twitter and instead will document mayhem primarily through an existing notification system run through a city Internet site. Police Chief Cathy L. Lanier and her top spokesman said the idea is to streamline the agency’s various social-media accounts and avoid duplication.

The AlertDC notification — is now the place to go for a list of crimes as they happen. Police will still tweet about high-profile cases, Lanier said, and the feed also will include information on wanted suspects, missing people and other department news.

“We’ve chosen which social media we use for which type of information,” Lanier said.

The change was evident on a recent Monday when five people were shot, eight people were robbed — three at gunpoint — and a woman held up a bank.

The more than 96,000 followers of the D.C. police Twitter account saw no reference to these crimes. The feed showed pictures of seized guns, an alert for a missing child, officers at community gatherings and an officer stopping traffic so a family of ducks could cross the street.

Breaking alerts on city crimes will continue to be posted through AlertDC, which has historically distributed such information and is run by the District’s homeland security agency. Residents can register and have information about shootings and robberies sent to their phones by text or email, along with announcements on street closures, water main breaks, power outages and severe weather threats.

The District says 164,921 people are registered with AlertDC, with 20,981 receiving crime alerts. The site allows users to get news focused on areas near specific addresses, such as homes, schools and businesses.

Police said their Twitter followers will still see posts on major incidents, typically crimes with broad impact or great public interest. For instance, when five people were shot in a matter of hours — two fatally — on May 16, police posted one notice on Twitter summing up the incidents.

Some activists and others said they are concerned about the change because they have relied on Twitter to be informed about violence in the city.

Richard Lukas, who lives in Hill East and helps run a Twitter feed called DCSafetyNet, which advocates for safe neighborhoods, noted that Twitter is universally used by other police and government agencies as a one-stop news source.

“Why would the D.C. government make less information available, not more?” Lukas said, adding that violent crime is slightly up this year. He said AlertDC “does not sound like an improvement” and complained that taking breaking crime news off Twitter “will reduce transparency.”

He suggested that the city should launch a separate Twitter feed devoted to breaking crime, much like D.C. police did for traffic. “This change is quite disappointing and seems more political than rational,” he said.

Gary Butler, an advisory neighborhood commission member from Southeast, also said he turns to Twitter to track crime. “I need to know when something happens, where it happened and how, and whether a suspect is on the loose,” he said. “Some of the stuff we’re now getting from police is not relevant. And stuff they put up as news I already know about from the neighbors. That’s not how it’s supposed to work.”

D.C. Council member Charles Allen (D), who represents Ward 6, which includes Capitol Hill, has pushed police to tweet more information about arrests and other enforcement actions along with breaking crime news, saying it would give residents a more complete picture of criminal justice issues in the city. “It sometimes doesn’t do justice to the work the police are doing when they are closing cases,” he said.

Lanier said she has received no complaints about the change and noted there are now separate streams of unique information, and people can follow some or all of them. She said her department is among the most open for dispensing information.

The police will continue to use Twitter to post videos of crimes for which they need help solving, along with updates on interactions with residents, they said. Yahoo bulletin boards allow residents to chat with one another and their police officers about crime relevant to their neighborhoods, and view arrest and crime logs. The department website has statistics and other information about the department.

Taking breaking crime news off Twitter goes against the practice of many major departments, which have used the platform both as a public service and a public-relations tool. Still, there’s debate about what kinds of information to post to Twitter.

A former Baltimore police spokesman in 2013 proposed not tweeting certain crimes, telling the Baltimore Sun that “the department is not going to tweet out every time a drug dealer shoots another criminal in the leg for nonpayment” but would instead tweet only “instances where nonfatal shootings involve citizens, public safety issues.”

That spokesman, and the policy, were quickly gone.

Prince George’s County police tweet out all homicides, rapes by strangers, fatal car crashes and critical missing people. Lt. Dave Coleman said other items are judgment calls: Are there photos to help track suspects? Is the crime part of a trend that impacts a community, such as a series of break-ins? Is it a crime of significance in which a victim was targeted at random?

“It’s going to be a balance of how much would be useful to put out and how much the community would want to know,” Coleman said. “We don’t want to flood people with everything, because the important things can get lost.”

Lynh Bui and Justin Jouvenal contributed to this report.