Police nationwide were on the lookout Monday night for an ex-convict suspected of killing two people and raping a teenage girl in a 24-hour crime spree.

Stephen Stanko (search), 37, is suspected of strangling a female librarian he lived with in South Carolina and shooting a man to death before stealing his pickup truck.

"He is very dangerous," Horry County police Lt. Andy Christenson said Monday. "Anybody who's capable of doing what he did ... is considered armed and dangerous."

Stanko was released from prison nearly a year ago after serving 8 1/2 years of a 10-year sentence for kidnapping. In a book he co-wrote with two professors, Stanko vowed he would never return to jail.

Sheriff Lane Cribb said a search of Stanko's residence pointed to an interest in serial killers.

"We found a lot of information about serial killers," Cribb told FOX News. "He just seems to be real interested in serial killers, and he started out heading that way," Cribb said, referring to the crime spree.

Stanko was known as someone who didn't mind sharing his experiences in prison with others.

"He seemed to feel comfortable letting people know that he was an ex-con," said John Gaumer, who was in a library book group with Stanko. "It didn't seem to bother him."

Stanko co-wrote "Living in Prison: A History of the Correctional System With an Insider's View" while in prison with the help of two criminology professors.

One of the professors, Gordon A. Crews (search), told Florence television station WBTW he knew Stanko was having a hard time adjusting to life on the outside.

"Nobody wants a convicted kidnapper working at Best Buy with them," Crews, a criminal justice professor at Roger Williams University in Rhode Island. "The last time I spoke to him, he was very, very depressed. He was on the verge of giving up," Crews said.

Several calls to Crews and the other professor, Wayne Gillespie (search), were not returned to The Associated Press.

Stanko had worked as a salesman for Stucco Supply in Myrtle Beach for a month, but his boss fired him a week ago. Jeff Kendall, the company's general manager, described Stanko as a smooth talker who was upfront about his time in prison, but was unreliable and brought in few sales.

"He wanted to do everything," Kendall said. "I was the one that gave him a chance. I said, 'I'll give you a chance, but from there, it's up to you."'

Police said one of the victims was 43-year-old librarian Laura Ling, who shared a home with Stanko and was found strangled Friday.

Gaumer said Stanko met Ling at the library where the ex-convict had said he was working on research for his book.

"He was a well-dressed, slick, smooth-talking individual. He came across well polished," said Gaumer, who is the director of the Horry County Memorial Library.

The other victim, 74-year-old Henry Lee Turner, was found shot to death in his home Saturday. Stanko and Turner knew each other, but it was not clear what their relationship was, Christenson said.

"We believe that Stanko has targeted senior citizens in the past in an effort to scam them out of money," Christenson said.

Turner's 1996 Mazda pickup truck with South Carolina license tag 709 PYJ was missing, according to the Horry County Police Department. Police think Stanko stole the truck, and asked people in North and South Carolina to watch for it.

The Associated Press contributed to this report.