STATE-NEWSRICHMOND, Va. (AP) _ A law professor says a decline in death sentences in Virginia is at least partly due to more vigorous legal representation during the sentencing phase of capital murder trials. Brandon Garrett of the University of Virginia released results of his study of Virginia’s death penalty Monday. Garrett compared the 21 capital murder trials since 2005 to a group of 20 such trials from 1996 to 2004. He found that the sentencing phase for the older group of trials averaged less than two days while the average for the more recent trials was four days. That’s because defense lawyers are calling more witnesses than before to present evidence that could help their client.  More than half the recent trials resulted in life sentences — double the previous rate.