1.
If you ~ something, you discover it after some searching. (INFORMAL)
...journalists who are trained to ~ sensation or scandal.
PHRASAL VERB: V P n (not pron)
2.
When a dog used by a group such as the police sniffs out hidden explosives or drugs, it finds them using its sense of smell.
A police dog, trained to ~ explosives, found evidence of a bomb in the apartment.
PHRASAL VERB: V P n (not pron), also V n P