WASHINGTON - The FBI thought it was closing in on Joran Van der Sloot in the notorious Natalee Holloway missing-teenager case, and he was videotaped and paid $25,000 in a sting operation. But when the agency delayed his arrest to help build a criminal case, he took the money and headed for Peru, where authorities say he has confessed to killing a different young woman.

The investigation of Van der Sloot in the Alabama teenager's case simply was not far enough along to have him arrested, the FBI and the U.S. attorney's office in Birmingham said Wednesday.

Holloway disappeared on the island of Aruba on May 30, 2005.

Van der Sloot is now expected to be charged with murder in Peru in the killing, exactly five years later, of business student Stephany Flores, 21, whom he met playing poker at a casino.

In his hotel room, Van der Sloot strangled Flores with his two hands and smashed her in the face with an elbow, the chief of Peru's criminal police, Gen. Cesar Guardia, said in Lima.

"He's irascible. He has no self-control," Guardia said yesterday. He's also very calculated, the general said, taking Flores' cash, about $300 in Peruvian currency, and two credit cards.

The 22-year-old Dutchman's confession was so thorough - and backed by such conclusive evidence - that police decided to waive the usual crime-scene visit, Guardia added.

Police were to formally ask prosecutors today to charge Van der Sloot with murder, for which he would face from 15 to 35 years in prison if convicted.