The Missouri law enacted this year designed to keep certain felons in prison longer is not having an immediate effect on the prison population, but may eventually help keep already increasing numbers up.

Senate Bill 763, popularly known as the Truth in Sentencing Law, requires people convicted of one seven particular felonies to serve at least 85 percent of their terms. The law applies only to those who were charged after Aug. 28.

Tim Kniest, public information officer for the Missouri Department of Corrections, said the law doesn't mean the department will get more prisoners, just that some will be staying longer.

"The impact will be late in the sentences," Kniest said. "It will be some time before we start to see an impact."

The sentencing law applies to the so-called Seven Deadly Sins -- first- and second-degree murder, first-degree assault, first-degree robbery, rape, sodomy and drug distribution.

Even under the old standards, those with such convictions would have been unlikely candidates for parole. However, prisoners who may have previously been released after serving two-thirds of their terms or less, will stick around a while longer.

Thus far, only one offender has been sentences under the new guidelines in Cape Girardeau County. He received a 25-year sentence and will serve at least 21.25 years. Previously he might have been released after 7.5 years.

Because the guideline is new, it will be a while before results can be determined.

"The crime has to have been committed after Aug. 28 of last year and then that person has to be prosecuted and depending on the jurisdiction and the offense that takes some time," Kniest said.

Even before the law, increases in prison populations have jumped significantly. In 1994, the Department of Corrections experienced a net gain of 5.25 inmates a day -- a sizable increase from the 1.7 additional prisoners once considered the average. At one point this year, the department was taking in nine new inmates a day, Kniest said. However, that figure was from earlier this year and has likely changed.

To offset additional inmates, the department works to treat those whose crimes resulted primarily from drug and alcohol abuse. Treatment and parole of those offenders helps create more room for more dangerous criminals. Kniest said the objective is to "focus resources on those people who you think can be turned around."

To keep such people on track once released, parolees must participate in after-care programs supervised by probation officials.

"There is a good chance that people treated for those problems will not come back," Kniest said.