The Polish Supreme Court has reduced the prison sentences of four secret policemen convicted of the kidnap-murder of outspoken, pro-Solidarity priest Jerzy Popieluszko, the government said. Popieluszko was one of the best-known priests in Poland, and his 1984 murder outraged this heavily Roman Catholic nation. Spokesman Jerzy Urban said the court decision was made for "humanitarian reasons." Urban said the high court ordered a 10-year reduction in the 25-year sentence of the ringleader, Capt. Grzegorz Piotrowski. The 15-year term of Col. Adam Pietruszka, charged with instigating the murder, was reduced to 10 years. The other reductions were not specified.