A number of tests have been conducted on psychics detectives, using control groups, to try to establish any psychic ability relating to crime solving. One of the earliest was carried out by Dutch Police officer, Fillipus Brink in 1960. He conducted a year-long study of psychics, but found no evidence of any crime-solving abilities. Another study was conducted in 1982 where evidence from four crimes was given to three groups: psychic detectives, students and police detectives. The clues related to four crimes, two crimes that had been solved, and two that had not been. The study found no difference between the three groups in ability to indicate what crimes had been committed by looking at the evidence. Some flaws in the scientific method were apparent in these two tests. A further test was conducted in 1997, this test focusing on improving on the scientific methods used in the previous tests. This study used two groups, one consisting of three students from the University of Hertfordshire, the other group consisting of three psychics (two psychic detectives and a non-detective psychic who had a media profile and had been endorsed by police due to his abilities). The two groups were shown three objects associated with three serious crimes. They then advocated theories, but once again, no difference was found in terms of the accuracy between the two groups.