One of the suspects in the shooting of AmeriCorps volunteer Joseph Massenburg in New Orleans has been arrested. Glen Emerson, 18, was grabbed and charged with second degree murder, according to the New Orleans Police Department.

An anonymous tip led investigators to the Lexus SUV and another vehicle used in a separate June murder, both reported stolen. Emerson was apprehended attempting to flee out the window of a nearby apartment. An adult male and a juvenile male were also arrested at the scene, though neither is considered a suspect in Massenburg’s murder.

Emerson was arraigned on June 28 and bond was set for $1 million, according to court records. A preliminary hearing is scheduled for July 11 and Emerson remains in Orleans Parish Jail.

Massenburg’s murder appears to be a tragic case of mistaken identity. “The shooters were targeting a rival gang member when they struck Mr. Massenburg by mistake,” said Sgt. Nicholas Gernon, NOPD homicide section. At least one suspect is still at large, according to Gernon.

Emerson is believed to have been the driver of a white Lexus SUV that was identified by witnesses. He is reportedly a member of a gang known as the Mid-City Killers. Massenburg was believed by the murderers to be a member of a rival gang.

Massenburg, 18, of Matteson, Ill., had arrived in New Orleans on his AmeriCorps National Civilian Community Corps (NCCC) teams’ first project on March 12. His team was working with Green Light New Orleans, a nonprofit focused on energy efficiency. On the evening of April 1, he was gunned down on a street corner in the Leonidas/West Carrollton neighborhood, just blocks from where he worked. He was pronounced dead at a local hospital soon after.

One week after Massenburg’s murder, Crimestoppers Greater New Orleans, a nonprofit that helps police investigations by collecting anonymous tips, doubled its standard reward, to $5,000. Executive Director Darlene Cusanza said her organization doubled the reward “because of Mr. Massenburg being a volunteer, someone trying to help. It’s something our organization felt strongly about. It’s a terrible crime.”

Cusanza said the police have received tips via Crimestoppers and from the community, and could not determine whether the identification of Emerson was due to Crimestoppers. “We’re still getting tips,” she said. Crimestoppers rewards are paid in upon arrest and indictment of suspects.

Massenburg’s death is the first homicide in NCCC’s 20-year history. According to acting press secretary Samantha Jo Warfield of the Corporation for National and Community Service, the government agency that oversees AmeriCorps, there have only been “a handful of total deaths” of active AmeriCorps volunteers, though Warfield declined to comment on specifics.

NCCC is a program for young people, ages 18 to 24. Members serve for 10 months on teams of eight to 12 and are based out of one of five campuses in Colorado, California, Iowa, Maryland and Mississippi. They complete a large variety of projects, from disaster relief to work in national parks.

Shortly after Massenburg’s murder, his team and another NCCC team were pulled out of New Orleans and returned to their Vicksburg, Miss., home campus for counseling. Warfield said that counseling is a regular occurrence for NCCC members. “They might see things they need help processing” while on assignment, said Warfield. After the NCCC teams were pulled out of the city, there were about 900 AmeriCorps members left in New Orleans.

“This young man was serving his country, making a difference through service to others,” said Kate Raftery, AmeriCorps NCCC director via a statement shortly after the murder. “His death is a tragic loss for his family, his friends, and our program. The safety of our members is a top priority. We work closely with local partners to provide a safe environment for all of our members in which to serve and live.”