Maine State Police have charged a Portland man with murder after the alleged hit-and-run killing of his girlfiend at Acadia National Park more than a week ago.

According to the Press Herald, investigators are attempting to locate 35-year-old Raymond Lester, who they say was behind the wheel of his 2016 BMW X3 when it struck and killed Nicole Mokeme at the Schoodic Institute in Winter Harbor.

An arrest warrant was issued last week by an Ellsworth, Me., judge but was not announced until Monday (June 27). Maine State Police spokesperson Shannon Moss said an affidavit of probable cause has been ordered impounded and that they are searching for Lester, but didn’t provide any information about their search progress, according to the Press Herald.

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Mokeme was killed at a retreat for Black Mainers she organized over the Juneteenth holiday week. She is a longtime activist, organizer and leader in Portland’s Black community, as well as the founder of Rise and Shine Youth Retreat, the Press Herald reports. The event offered outdoor excursions and deep rest at the campus in Acadia National Park.

Authorities haven’t released details about what may have motivated the hit-and-run killing. Investigators believe she died sometime between the evening of June 18 and the early morning hours of June 19.