This peaceful spot in the middle of the 54-acre Brookside Gardens recalls a very somber span of three weeks in October 2002 when local residents were gripped by fear as a series of random and mysterious killings unfolded across Washington, D.C., Maryland, and Virginia. The perpetrators left behind a trail of dead and wounded on a bloody cross-country trek between February and September 2002, during which they shot and killed seven people and wounded seven more. They arrived in the D.C. area some time between late September and early October, after…