The police had been following him for weeks but they could not prove his involvement in the bombing WordNet 3.0 & Open English WordNet

The plaintiff also stresses that the store as a whole, and the customer exits especially, were closely surveilled. Wiktionary

Alexandre of London v. Indem. Ins. Co., 182 F. Supp. 748, 750 (United States District Court for the District of Columbia) (1960), cited in Bryan A. Garner. A Dictionary of Modern Legal Usage (2nd ed., 2001) p. 861. Wiktionary