LONDON (AP) _ Colin Ireland, who confessed being the killer who stalked London's gay community and murdered five men, was sentenced on Monday to life in prison.

Prosecutor John Nutting said Ireland set out to become a serial killer, telling people he would have to kill at least four people to be classified as one. Ireland carefully planned and executed the crimes, spending hours after each murder clearing away evidence, Nutting said.

One of the victims was an American, Perry Bradley III, a businessman from Sulphur Springs, Texas, who lived in London.

Ireland, 39, turned himself in on July 20 after police released a security camera picture of him walking behind the fifth victim at a subway station shortly before the murder.

He had been held without bail, and he confessed in August, according to testimony on Monday at the start of his trial in Old Bailey Central Criminal Court. It was the first opportunity Ireland had to enter a plea.

Ireland strangled or suffocated the men in their London homes between March 8 and June 15. Each time, he telephoned police, a national newspaper or a suicide hotline with precise details of the crime. He also threatened to kill a new victim every week.

Police said four of the victims were known to be homosexuals. They said they had no evidence that Bradley was gay.

But Nutting told the court that ''the victims all had in common the fact that they were homosexual'' and all frequented a pub popular with homosexuals in south London.

''He chose a vulnerable group as his intended victims - homosexual men who indulged in sadomasochistic sex, thus enabling him to tie them up with no resistance from them before killing them,'' the prosecutor said.

Before every murder, Ireland emptied his pockets of everything but money so nothing could fall out and incriminate him, Nutting said. After each killing, he spent hours removing all traces of his presence, even taking away half- eaten food and dishes. He cut up and destroyed the clothes he wore.

Nutting said Ireland stressed in his interviews with police that he was not a homosexual and did not have sexual relations with any of his victims.

''To take one human life is an outrage. To take five is carnage,'' Judge Michael Sachs said in passing sentence.

Ireland's mother, Pat, sobbed when he was sentenced. His stepfather, Alan Williams, said life in prison was justified.