A convicted murderer escaped from a medium-security prison in northwestern Pennsylvania by hiding in a garbage can, state police said.

Malcolm Kysor, 53, of Erie, was discovered missing during a routine check around 4:30 p.m. Sunday and remained at large Tuesday.

Kysor hid in the can, which was pushed onto a loading dock and hauled away on a pickup truck, according to a criminal complaint filed against Kysor.

Surveillance camera video showed that another inmate, John Gromer, 26, of Philadelphia, helped Kysor by placing a box and plastic bag over him to help conceal him, then pushing the can onto the back of the open-bed pickup truck, police said. Investigators said Kysor told Gromer someone on the outside was going to pick him up.

Erie County District Attorney Brad Foulk said he would decide whether to file charges against Gromer.

Kysor has been serving a life sentence since 1988 for an early 1980s murder in Erie County. He was moved to the State Correctional Institution-Albion in April.

The prison houses about 2,300 inmates and is located just outside downtown Albion, a small town about 20 miles southwest of Erie. Albion is about 10 miles northeast of Pierpont, Ohio, the border town where Kysor's victim lived.

A lockdown also continued at the prison, authorities said.

Kysor was convicted in January 1987 of first-degree murder in the beating death of Barney Fenton, 40.

He was arrested in June 1981 for drunken driving in Fenton's car. Nearly a year later, Fenton's remains were found buried along Interstate 79 near the Millcreek Mall just outside Erie.

Kysor, who is white, is about 5-foot-8 and 160 pounds. He has brown hair and eyes and several tattoos: a devil, heart and snake on his chest; a flower and eagle on his right arm; a rose with two hearts and a flower on his left arm; and a devil with a woman and an angel with a horse on his abdomen.

He had previously served time for receiving stolen property, police said.

Citizens were warned not to approach Kysor if they spotted him, and to contact police. The FBI announced an unspecified reward for information leading to his capture.

Kysor's escape is the first by a convicted murderer at a state prison since 1999, when three inmates — including two convicted murderers — broke out of two state prisons within two weeks.

Convicted four-time killer Norman Johnston escaped from the Huntingdon state prison on Aug. 2 that year and was free for nearly three weeks before he was captured peacefully about 25 miles west of Philadelphia.

Two cellmates broke out of the state prison in Dallas on Aug. 16, 1999. Michael McCloskey, imprisoned for murder, and Anthony Yang, serving time for arson, were captured four days later.

In both escapes, the inmates cut window bars and put handmade "dummies" in their beds to fool guards.