In this paper, data on crime detected by the Slovenian police and changes and factors that influence the work of the police, are presented. Included are criminal offences that were detected by the police, and consequently, do not fully reflect the security situation in the country in the last year. Priorities of the police include detection and investigation of economic crimes that causes large financial damage, offences to the detriment of the Slovenian banking system, organised forms of corruption and also the fight against organised crime and serious international crime. In 2015, construction of the National forensic laboratory was completed, and is of utmost importance to the police, because without the support of forensic and forensic investigation, successfully dealing with criminal offences would not be possible. The Laboratory itself has the appropriate infrastructure and provides a safe work environment in accordance with accredited and internationally recognized methods and standards. In 2015, the Slovenian police investigated 68,810 (87,474 in 2014) criminal offences, which represented 21.3% fewer than the previous year. Detection and investigation of criminal offences was slightly more successful than in 2014. The Police investigated less crime because of the massive engagement in solving the migration crisis from September 2015 onwards. The proportion of criminal offences, which were detected by police activities, increased from 15.0% in 2014, to 15.2% in 2015, and increase of 0.2%, while the proportion of investigated criminal offences increased from 51.8% to 52.0%, or 0.2%. The Police estimated that 454.8 (755.3 in 2014) million euros of damages was caused by conducted criminal offences in 2015, or 39.8% less than in 2014. Damage caused by economic crime decreased significantly from 506.6 in 2014, to 194.3 (in 2015 million euros). The Police investigated 25.2% fewer criminal offences against the economy in 2015 in comparison to the 2014. Its share in total crime has decreased from 19.2% in 2014, to 18.2% in 2015. Overall, crime has decreased 20.4%, while the number of investigated criminal offences in general has decreased from 45.6% in 2014 to 42.9% in 2015. The scope of juvenile crime 31.5%, while crime against sexual integrity decreased 12.8%, and the investigation of organised crime increased for 1.3%. Comparisons over the last 10 years showed that in the period from 2006 to 2015, the number of investigated crimes and the proportion of criminal offences that were detected by the police were the highest. Compared to 2006, the number of investigated crimes increased 11.1%, while the number of criminal offences detected by the police increased 6.2%.