Detailed Instructions: In this task, you are given an article. Your task is to summarize the article in a sentence.
Problem:The papers show that police believe increases in certain types of violence may be down to new psychoactive drugs and increases in alcohol consumption.
There could also be a "perception" that Police Scotland is doing less "intervention work", the documents say.
The papers were obtained under the Freedom of Information Act from the police's own Violence Reduction Board.
The new body, which was set up a year ago, highlights the shift in violence away from city centres and public areas.
It said more people were drinking alcohol in "private spaces" and new drugs, known as "legal highs" before they were banned at the start of the year, were causing violent behaviour.
Violence Reduction Board papers from January state "more crimes of violence are occurring in people's homes, often behind closed doors".
They say: "Since 2009/10 we've seen a big swing in the balance from public space to private space, meaning the increasing number of violent crimes in private space is now becoming a concern (increased from 34% in 2009/10 to 43% in quarter one of 2015/16)."
The papers add: "The traditional approach to tackling public space violence does not necessarily translate to policing violent crime happening in the home.
"Violent crime in private space does not just relate to domestic abuse and we need to better understand why this is happening.
"What we do know is that there is a clear link to alcohol."
On Wednesday, BBC Scotland revealed that serious assault, murder and robbery had all increased in the past nine months compared to the same period in the previous year.
Police Scotland said violent crime was down over the past five years and crime overall was at a 40-year low.
However, concerns have been raised about why recent increases in some crimes have taken place.
The VRB papers questioned whether it could be related to the police significantly reducing their use of stop-search tactics but found "no conclusive correlation".
The papers also revealed that senior officers were concerned that there were a number of potential reasons to "explain the increases" including:
The documents also said that the police's own draft Violence Strategic Assessment "shows analysis indicating there is an increase in the use of weapons in violent crimes in West Central Scotland".
Figures for the past nine months indicate a 4.4% increase in handling bladed weapons.
The papers say that behind the scenes police and the Violence Reduction Unit (VRU) are working to identify why there may have been increases to try to tackle "how to address the challenges ahead".
Will Linden, acting director of the Violence Reduction Unit Scotland, said it was a "complex picture".
He said Scotland had seen a massive reduction in violent crime committed by young people over the past decade by concentrating on tackling knife crime.
Mr Linden said an increase in violence levels had been identified among those aged 21 to 30 and that was the age group that now needed to be targeted.
He said: "We won't address violence solely by policing because if the violence is now not happening on our streets but happening in our houses then policing isn't going to help that."
The VRU director said tackling alcohol consumption was a key factor.
"The relationship between violence and alcohol has long been toxic for Scotland," he said.
"Over the past few years we have been lucky to see decreases in the level of alcohol consumption which is correlated to decreases in the level of alcohol-related violence.
"However, in the past two years we have seen a reversal of that trend.
"This increase may have a significant impact on the levels of violence we are seeing."
Solution:
More violence is happening behind closed doors in people's homes, documents obtained by the BBC reveal.