Less than a year ago, Southwest Philly heavyweight boxer Levon Warner was knocked out in the first round of a fight at the legendary Blue Horizon - but even harder times lay ahead.

"I wasn't seeing what I wanted to see," Warner's former trainer Sloane Harrison said yesterday. "He took some shots. He wasn't boxing like I know he could box."

Harrison, who trained Warner at Kingsessing Recreation Center in Southwest Philadelphia, had a heart-to-heart with the now-38-year-old pugilist. "I encouraged him to retire."

Now, police say that Warner - an ex-convict who left the sport with a 6-5-2 record - made a horrible choice of a new career.

Yesterday, the former boxer was behind bars for his role in a bank holdup and the brutal slaying of police Sgt. Stephen Liczbinski, who was shot by the suspects after he pulled over their getaway car in Port Richmond Saturday.

One of Warner's alleged criminal cohorts, Howard Cain, 33, of Clearfield Street near Sheridan, was shot to death by police. The other, Eric DeShawn Floyd, 34, is on the lam.

Floyd is believed to have lived at the Clearfield Street address with Cain. Law-enforcement sources said they believe that Cain, the mastermind of Saturday's holdup, and prior bank robber Floyd apparently became friends in prison, and later teamed up on the outside with the ex-boxer Warner.

All three men "are known to law enforcement," said Deputy Commissioner William Blackburn.

Warner, of Westminster Street near 54th , was found guilty in 1997 and served 10 years for armed robbery, according to published reports.

Floyd escaped from a halfway house in Berks County, police said during a news conference yesterday.

The fugitive pleaded guilty in 1995 to robbery, possession of an instrument of crime and criminal conspiracy for a November 1994 incident, according to court records. Judge Gary Glazer sentenced Floyd to one to five years for the crimes, and ordered the felon to pay $185 in court costs.

Floyd was sent to the drug treatment facility Adappt Treatment Service in Reading, according to court records.

Before his alleged crime, Warner was "a pretty good fighter," said Harrison, who said he trained him for a couple of years. "He wasn't no top contender."

Warner is a 1987 University City High School graduate, according to an Inquirer article. He turned pro in 1993, boxing three times before his first Philadelphia bout at the former Viking Hall, now the New Alhambra, on Swanson and Ritner streets in South Philadelphia, said boxing promoter J Russell Peltz.

His first-round knockout by Joey Abell was last Sept. 7 at the Blue Horizon.

"He was a pretty decent prospect, but he lost the time," said Peltz, referring to Warner's time in prison. "He was 38 years old with not many fights."

Philadelphia cops descended upon the bright red, two-story property on Clearfield Street,where Cain and Floyd had been living, at around 2 p.m. Saturday, said a 40-year-old neighbor, who declined to give her name. They closed off streets around the house.

She said she didn't know Cain and Floyd, but had seen them go in and out of their home with other men. "There are a lot of people who live there. It's like a boarding house."

Police Strike Force officers were interviewing a few young men on Sheridan near Clearfield. They apparently pulled out three young men from one home, one of them said.

Larry Trippett, 18, an Edison High School senior, watched as strike-force officers questioned his cousin and another young man. Trippett said he was lying on the floor, watching a movie when cops burst into his house.

"They pulled me out. They said my little cousin looks like the suspect," he said, referring to Floyd. The young men were released and quickly went back inside their house.

An older man watching the proceedings from a second-floor window shouted down commentary regarding what he perceived as police abuses. "They're trying to blame that s--- on somebody!" *

Staff writers Bernad Fernandez, Christine Olley, and Kitty Caparella contributed to this report.