Biography
Mark Cook was the only African-American member of the George Jackson Brigade and the last to join the Pacific Northwest militant prisoner-solidarity formation. He participated in the January 23, 1976 Tukwila bank robbery that killed Brigade member Bruce Seidel and led to the arrest of Ed Mead and John Sherman; he avoided arrest at the scene. Days later, he carried out the armed liberation of John Sherman from Harborview Medical Center in Seattle, where Sherman was being held under guard for medical treatment of her bank-robbery wounds; a King County deputy was wounded in the operation. Cook was arrested shortly afterward and convicted in Washington state court. He served 24 years in the Washington State Penitentiary at Walla Walla — the longest of any of the Brigade’s members.
Inside, he organized a chapter of the Black Panther Party at Walla Walla, founded the PIVOT post-release re-entry program, and organized the long-running CONvention prison-organizing seminar. He was released in 2000.
Reviewed historical source
The Freedom Archives copy of the Guerrilla USA book proposal reproduces a named early induction photograph of Mark Cook. The photographed placard reads “M. E. COOK” and “6-10-58.” This is an earlier institutional-history lead, but a portrait and abbreviated date alone do not establish a complete separate conviction or actual prison-admission and release dates. The same proposal captions Bo Brown at the Pleasanton federal women’s institution in 1985. Its collective descriptions are not individual custody endpoints.
The Summer 1995 Breakthrough prisoner-support directory lists Mark Cook, with historical prisoner number 027100, at PO Box 777, Monroe WA 98272. This is the directory’s historical correspondence address, not a current mailing instruction or present custody claim. It supplies no admission, transfer or release day and no completed custody total.
Breakthrough, Summer 1995, Write Through the Walls, PDF page58.
The Fall 1992 prisoner-support directory lists Mark Cook under historical federal register 20025-148 with a mailing location at FCI Sheridan, Oregon. Later 1994 and 1995 directories print the different Washington number 027100 at Monroe. The older federal reference is preserved here as dated source information; the existing 027100 field is retained. The listings do not establish a precise transfer, new original admission, release or continuous duration.
Seattle Under Attack reports Cook’s actual arrest at his Seattle home two days after Sherman’s March 10 escape, while the existing record dates arrest March 11. That one-day conflict is preserved rather than silently overwriting the established date. It describes Cook’s earlier Walla Walla prison organizing, a May 12 additional assault charge over Sherman’s escape, increased $250,000 bail, and a May 19 conspiracy indictment. The June 21 trial remained scheduled, not completed. The article’s claims about weak evidence are attributed advocacy, not a court finding.
The chronology reports an August 6, 1976 federal disposition of twenty-five years for bank robbery, five for weapons and another five-year conspiracy term involving Sherman’s escape. Arrest is dated March 12 versus the existing March 11; no endpoint overwritten. Whitnack’s July 24 letter places Cook in the men’s half of the Seattle jail and reports an appeal. Informant and unfair-trial claims are attributed advocacy.
