Local security officials remained on high alert Sunday during the 10th anniversary of 9/11, with all 3,800 D.C. police on the streets for the weekend and police in surrounding counties patrolling Metro stops and ceremonies. Police hunted for two stolen vans around D.C., worried that they might be the vehicles chosen to deliver the “credible, specific threat” that federal officials warned of Thursday. The two U-Haul vans were stolen in Prince George’s County; authorities said three more trucks were missing in New York City.

But Prince George’s County police found one of the vans about 9:40 p.m. Saturday night, abandoned near the 900 block of Marcy Ave in Oxon Hill. Police said they’re still investigating who stole the vans and why.