31.   They hung up, but police tracked the call.

32.   This makes it extremely difficult for police to track down the people behind the ring, investigators say.

33.   While this requires police to track noncriminal activity, the department said the practice is legal and provides hints to future criminal acts.

34.   While police can track those guns back to their original owners, they must witness the unlawful sale of a weapon to prosecute.

35.   Police have tracked down and arrested a man who stabbed a Turkish soccer fan, injuring him slightly, the state news agency TASR reported Monday.

36.   Police have tracked down the family of Qadeer, who identified himself to Pearl as Arif, in a village in Punjab province.

37.   Police tracked down the mother and grandmother of girls, who gave poverty as the reason for selling them into sexual slavery.

38.   Police have tracked Breton and Basques separatists in southwest France and Spain to the September theft of about eight tons of dynamite in the town of Plevin in Brittany.

39.   Police track down and surround the heavily armed gang, which threatens to execute the captives.

40.   Police tracked down and surrounded the heavily armed gang, which threatened to execute the captives.