Question: when was fingerprinting first used by the police?
Answer: the early 20th century, In 1840

difficult to alter, and durable over the life of an individual, making them suitable as long-term markers of human identity. They may be employed by police or other authorities to identify individuals who wish to conceal their identity, or to identify people who are incapacitated or deceased and thus unable to identify themselves, as in the aftermath of a natural disaster. Fingerprint analysis, in use since the early 20th century, has led to many crimes being solved.  This means that many criminals consider gloves essential. In 2015, the identification of sex by use of a fingerprint test has been reported.