Two convicted murderers who held two women hostage at a state prison before releasing them unharmed have histories of violence inside jail, prison records show.

Inmate Edward Robinson, 27, was disciplined by prison officials in 1985 for threatening another person and again in 1986 for assault. Robinson lost 180 days of compensation time that would have moved up his 1994 parole eligibility. He is serving a life sentence for killing a man with a gunshot in the back of the head.Inmate Angel Guzman, 26, was disciplined in 1987 for disruptive conduct and in 1983 had six months added to his 1989 parole date for a weapon's charge and for assault, prison records show.

Guzman, who has a tattoo on his forehead reading "Lucifer Prince of Darkness," is serving a life sentence for shooing his uncle during an argument over $70.

After taking the hostages Thursday, the two inmates demanded they be transferred to a federal prison outside New Jersey and that officials take no reprisals because of the hostage taking, Department of Corrections spokesman James Stabile said.

"The negotiators agreed that the grievances of the two inmates would be reviewed," said Gary Hilton, deputy corrections commissioner.

Robinson also asked to be allowed to call his mother, a demand Hilton said would be granted.

Annette Martin, a teaching assistant, and Joan Mason, a vocational counselor, were taken hostage a 9:07 a.m. Thursday as they conducted a teaching demonstration in the year-old Northern State Prison's library, authorities said.