A recent string of robberies in New Haven’s East Rock neighborhood has been connected to a crude weapons-manufacturing operation based out of a nearby residence.

A press release on Oct. 23, from NHPD spokesman David Hartman said that three suspects had been arrested for committing two robberies in the East Rock Park area. Authorities later found one suspect to be armed with a hand-made “zip gun,” an ad hoc weapon — typically engineered by amateur street manufacturers — that can cause serious harm and death. NHPD detectives later discovered that the weapon was one of about a dozen made and sold by another juvenile operating out of his residence on Mountain Ridge Road.

“Such crude deadly weapons pose a threat to both the victim and the shooter,” Hartman said in the release. “There is a possibility the weapon could explode or misfire. Anyone in possession of such a weapon is at great risk.”

The suspects were found on East St., which runs up downtown New Haven to the edge of the East Rock neighborhood. These three youths are believed to be responsible for both East Rock robberies, according to Hartman’s press release. One of these suspects was in possession of a zip gun, allowing police to obtain a search and seizure warrant that led to the arrest of the suspected manufacturer.

One day before Hartman’s press release, two East Rock robberies were also reported by Ronnell Higgins, chief of Yale Police Department, in a statement to all Yale faculty, staff and students. The first took place on Sept. 27 at 3:15 p.m., while the second happened on Oct. 19 at 1:30 p.m. In both cases, a Yale Law School student was targeted as he was jogging alone around Orange St. and English Dr. One victim had cash and a cell phone stolen, while the other was robbed of his iPod. The YPD reported that both victims were chased and assaulted by a group of at least four teenage males on bikes. It is unclear whether the two robberies described in Higgins’ email are separate from the robberies described in Hartman’s press release.

“While this is outside the boundaries of campus, it is a reminder that crime can occur anywhere, at any hour,” Higgins said in the statement. “I am hoping that information about these incidents will heighten your awareness and allow you to take actions to lessen your likelihood of becoming a crime victim.”

Higgins included safety tips on how to avoid being targeted in similar circumstances, suggesting that students avoid walking or jogging alone, particularly in an isolated area. Hartman closed his press release by urging the public to report any news regarding the manufacture, possession or use of the zip guns to YPD detectives.

Four New Haven residents interviewed in East Rock Park on Sunday said that they had not heard about any particular incidents of crime either in the park itself or in the general neighborhood.

Brian Gerena, a 35-year-old East Rock resident, said that the neighborhood is typically secure, especially compared to other areas in downtown New Haven. Gerena said local block watches and community policing make him feel safe in his neighborhood, but acknowledged that home invasions and similar crimes still happen occasionally.

“In the areas like [East Rock], it’s really nice and peaceful. But I also know it’s a target for crime, because [criminals] figure it’s a lot quieter and they can probably get away with it,” Gerena said.

East Rock Park regulations explicitly prohibit weapons in the park, which is normally closed from sunset to sunrise every day.