Good morning, Bulletin readers. Before the Parkland shooting, red flag laws were both rare and rarely used in the handful of states that had them. As legislatures have moved swiftly to pass or consider the measures, they have also become a more regularly used tool. A report out of Oregon is the latest to detail the types of cases in which red flag laws have been deployed to disarm people at risk of committing violence, include one man who threatened a school shooting and another who talked about shooting his ex-boss. That report, and more, below.

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WHAT TO KNOW TODAY

One person was killed and 17 others were wounded by gunfire at an all-night arts festival in Trenton, New Jersey, early Sunday morning. A 13-year-old boy was among the wounded. Officials say the shooting, which erupted at a venue hosting roughly 1,000 attendees, stemmed from a gang dispute, but many of those injured were bystanders. Reports indicate that the dead man, recently released from prison on manslaughter charges, may have been killed by responding police officers. Two other suspects were hospitalized with gunshot wounds. At least five other people sustained non-gun-related injuries.

Facebook will prohibit advertisers from showing minors ads for gun accessories. The new policy, which takes effect on Thursday, expands the social network’s existing ad rules, which ban advertisements for firearms sales. (Many gun sellers on the platform have easily skirted the prohibition, and Facebook continues to rely on users to report posts that violate the rules, rather than monitor profiles itself.) The restrictions will apply to vendors hawking everything from mounted flashlights to gun safes to military clothing.

Since it took effect in January, Oregon’s red flag law has been used to temporarily remove guns from two dozen individuals. The Oregonian/OregonLive requested public records from counties statewide to calculate how many gun owners have been affected by the law, which requires the subject of an extreme-risk protection order to turn in their weapons within 24 hours. The order then remains in place for at least a year. Through the end of April, 27 ERPOs were requested by Oregonians, and all but three were granted by judges. Among those whose weapons were temporarily confiscated were a man threatening a school shooting; a man who threatened to shoot the boss who just fired him; and a veteran who talked about shooting members of his church. Oregon’s red flag law narrowly passed the state Legislature last year. Since the Parkland shooting, the number of states that have similar policies on the books has doubled.

Meanwhile, Oregon gun groups are trying to disrupt a ballot initiative that would create a safe storage law. The Oregon Firearms Federation, as well as other state groups and members of the National Rifle Association, have asked the state Supreme Court to change the language of the measure, a move that narrows the window for qualifying the initiative for the ballot. The measure — which would require gun owners to directly supervise children using guns and to report lost firearms within 24 hours, as well as hold gun owners liable for damage caused by the weapon — must receive 88,000 signatures by July 6, but proponents cannot begin collecting signatures until the title dispute has been resolved. From The Trace archives: How a mass shooting carried out with a stolen gun inspired the measure.

Two Kansas City, Missouri, deputies were fatally shot by an inmate outside a courthouse on Friday. They were in a gated area used for transporting prisoners into court; while there, a man who was facing homicide and aggravated robbery charges got hold of a weapon and shot Deputies Patrick Rohrer and Theresa “T.K.” King. Officials did not provide details of how the inmate got possession of a gun, but did say the two deputies were following appropriate procedures.

ONE LAST THING 

An inverted American flag — widely recognized as a sign of distress — waved in the breeze at the summer’s first March for Our Lives rally in Chicago on Saturday. The Parkland shooting survivors teamed up with a group of local teens whose daily lives are wracked by urban gun violence in their South Side community. The young activists canvassed the neighborhood, seeking to register young, first-time voters ahead of the November midterm elections with the goal of pushing elected officials to enact gun reform.

The Chicago activists, some of whom first met with the student activist Emma Gonzalez in March, hope their association with the high-profile Parkland students will stop lawmakers and the outside world from writing off the urban shooting epidemic as a just a gang problem. The March for Our Lives organizers will continue their bus tour through 20 states this summer.