This data is from 2003, and shows that in 2003 76,459 Felons who were in prison for violent crimes were released.
The median time spent in prison was 2.6 years, with 6.9 years for homicide, and 9.4 years for murder. Based on re-arrest rates for released prisoners, as shown in the graph, an estimated 44,346 have been re-arrested by some time in 2006, including an estimated 9,443 who had previously killed someone.
Using an average prison time of 2.6 years and an average time before arrest of 1.5 years (half the 3ys). and only 58% of each successive group being arrested, I estimate these 76,459 felons will be arrested for 178,000 more crimes in the next 15 years.
If there is truly an interest in reducing criminal violence, it seems like we should stop letting violent criminal out of prison every 2.6 years.
Data below is from tp://www.ojp.usdoj.gov/bjs/dtdata.htm#time
..................................................Releases....Median Yrs......Est to be re-arrested within 3 years
Violent offenses...................................76,459........2.6........44,346
Homicide.............................................6,396........6.9.........3,710
Murder/nonnegligent manslaughter...........3,779........9.2.........2,192
Murder................................................2,907........9.4.........1,686
Nonnegligent manslaughter........................872........8.0...........506
Negligent manslaughter..........................2,326........3.8.........1,349
Kidnapping...........................................1,744........2.8.........1,012
Rape...................................................4,652........5.7.........2,698
Other sexual assault.............................10,757........2.9........6,239
Robbery..............................................22,385.......3.3........12,984
Assault...............................................26,746.......1.7........15,513
Other violent.........................................4,070........1.4.........2,361