St. Louis officials want to spend nearly $10 million to hire and train 160 additional police officers in response to a recent spate of violent crime that the mayor and police chief blame on a "Ferguson effect."

Mayor Francis Slay and Police Chief Sam Dotson acknowledge that proving a strict cause-and-effect relationship between the August fatal police shooting of Michael Brown and St. Louis' crime rates is impossible.

Robberies and aggravated assaults increased in 2014 compared to the previous year and became more pronounced after the black 18-year-old was shot and killed by a white Ferguson police officer.

The city recorded 159 homicides in 2014, its highest total since 2008 and the second highest total in 19 years.

Dotson suggests some were emboldened by looting, arsons and clashes with protesters.

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