Washington ? The government is prosecuting only about one out of four of those charged in connection with terrorism, according to a study that suggests federal agencies don’t agree on who is a terrorist.

People charged with terrorism often go free because the evidence wasn’t strong enough to bring them to trial, says the study by the Transactional Records Access Clearinghouse, a data research group at Syracuse University.

Since 2002, the percentage of terrorism cases that federal prosecutors declined to pursue has grown from 31 percent to 73 percent, the TRAC study found.

Nearly 6,000 of the close to 8,900 cases referred for prosecution by federal investigators between 2004 and 2008 were closed without action. Of the remaining cases, 2,302 people were convicted and 1,245 went to prison, the study found, and just 52 were sentenced to 20 years or more.