Victor Gant, a New Orleans cop, is under suspicion of murdering 24 people. But unless the FBI brings charges, he remains on the force - you can even call him at the office, says Daniel Jeffreys
"Victor Gant," said a deep voice at the end of the phone. I had dialled a number at the New Orleans Police Department. It was answered promptly, after three rings, as you might hope if you called a police station. Gant is a serving officer, but he is more than that: he is also the prime suspect in a murder investigation.

The target of the hunt is a serial killer who, investigators believe, has struck at least 24 times. The FBI think that Gant may be the killer but they don't have enough evidence for an arrest. So Gant sits at his desk, suspended from patrol duty. If you have his telephone number, you can call him and hear his Louisiana drawl: "I can't really discuss the case, you'll have to talk with my lawyer."

Gant became a suspect after Karen Ivester was found strangled. Her body was dumped in the swamp about half a mile from Interstate 55, just 30 minutes from the French Quarter of New Orleans. As local police combed the scene they found a second corpse, another young woman. Sharon Robinson had been drowned. She was still dressed in her work clothes, a uniform from the Harrah's Casino in New Orleans. Before death, her head had been shaved. In life, Robinson and Ivester had been best friends.

Police inquiries at the casino revealed that Robinson had left work on 29 April this year at 3am accompanied by Gant, a 33-year-old officer who was once her boyfriend. The New Orleans Police Department immediately named Gant as a suspect. Then the FBI announced that the man who killed Robinson and Ivester had also claimed 22 other victims.

Twenty-one of the killer's victims had ties to prostitution, Ivester included. Nineteen were known prostitutes, including one man. There were two other male victims and there is evidence to suggest they were also prostitutes. According to NOPD sources, each body carried some distinctive marks that matched through all 24 deaths.

Many police officers feel uncomfortable because Gant is still at work, still drawing his pay cheque. Others say the situation is typical of the NOPD's mismanagement. "It's a little bizarre," says a detective in the criminal investigation bureau. "I know Victor and I like him. I still see him regularly and my attitude has not changed towards him. I was surprised when the Chief said Gant was a suspect."

So was Gant's attorney, who says that the psychological profiling system which targeted Gant is dangerous. "The NOPD says Victor is under investigation for two of the murders," says John Reed. "The FBI says all the murders were committed by the same person. So that makes Victor a serial killer? I don't think so. He fits some of the psychological profile but so do a lot of people. It should not be used to launch witch hunts - it's only a profile. Where's the solid evidence?"

Gant is now awaiting the result of a DNA test. If he ends up in jail, it may be because of a common southern habit - he likes to chew tobacco, and a wad of plug was found near Ivester's body, saturated in saliva. Gant gave blood, semen and saliva samples to the FBI in June but they have not yet issued a report. Many of those concerned about the case, including relatives of the victims, have expressed astonishment at the more than four months' delay in publishing the results of the DNA test.

New Orleans is one of the most famous American cities yet its police department is in crisis. In the past 18 months, four NOPD officers have been charged with murder, nine others have been indicted on federal drug charges, the chief of detectives was fired for unethical behaviour and the supervisor of a vice squad was convicted of robbing bars and strip joints.

New Orleans has always been a city of contrasts. For centuries white affluence has thrived alongside black poverty. The glitz of the French Quarter soon disappears in adjoining neighbourhoods such as Treme and Algiers which are just a stone's throw from the French Quarter but light years from the tourist trail. The neighbourhood is fighting for economic survival, the streets are poorly lit and prostitution thrives alongside an active drug trade.

The FBI formed a task force to work the New Orleans case on 1 May. According to officers involved with the investigation, Gant has a record of suspicious involvement with prostitutes.

Gant used to patrol in Treme and Algiers. Several residents say a group of New Orleans police officers has operated a string of prostitutes in the area for years. Some say they've seen brutal beatings and threats of murder and a few have claimed Gant was an associate of one suspect group which allegedly ruled through intimidation.

On a recent Friday night the bars along Treme's Claibourne Avenue were busy and outside each one there was a small clutch of women working the street. Many are scared, some are aggressive and few were willing to speak. When they do, they insist on anonymity.

"The police and the politicians don't really care about us," said one. "It took over a dozen deaths before those motherfuckers lifted a finger to find the killer. I knew two of the three girls who died but I wouldn't tell the police about it. I'd be the next one dead if I did." The woman then went further. "I saw the girl called Peach just a couple of days before she was murdered. The thing is, some of the cops were running the girls around here, they were pimping. Some people say Peach got out of line."

"Peach" was the name used by Karen Ivester. According to FBI investigators, Gant had told some acquaintances that he disliked Karen Ivester because she had persuaded her friend not to join her in prostitution. Local papers report that the Treme prostitutes have been victims of an intimidation campaign by a group of rogue police officers.

FBI agent John Fleming confirms that NOPD involvement in prostitution is an element in the case. "A common thread in the victims was their membership of prostitution rings that seem to have been connected with a group of NOPD officers. Victor Gant has been associated with that group."

Multiple killers are notoriously hard to catch. Their victims are often prostitutes or drug addicts, street people with few ties and nobody to take notice if they go missing. The killers usually dump bodies in several different jurisdictions involving many separate police departments. With this in mind the FBI devised its Violent Criminal Apprehension Programme (Vicap): it was Vicap which suggested the New Orleans killings were the work of one man, and Vicap which Gant's attorney believes to be a flawed system that has wrongly identified his client.

Vicap begun in 1984, was designed to catch serial killers. It contains detailed information on over 18,000 murders with similar characteristics. The FBI has also compiled detailed profiles of more than 100 people who have been convicted of serial killings.

The murder data helps determine if a serial killer is at work; the profiles help define who the suspect might be. By early next year, Vicap will link up with five regional databases to create a national Vicap which will co-ordinate police forces from 50 states.

According to Greg Cooper, Vicap's programme manager, there are around 60 serial killers active in the United States at any one time. That figure has tripled in the past decade, suggesting Vicap has yet to contain the serial killer epidemic, but the FBI believes it has captured the profile.

"Nearly all serial killers are white males in their mid-twenties and thirties," says Cooper. "They have above-average intelligence and a calculating, methodical nature. A serial killer has usually experienced physical, psychological or sexual abuse plus some form of parental rejection. In later life they tend to be loners although they can often be charming with highly developed communication skills."

Except for his race, Gant fits most of the Vicap profile. His neighbours in the Algiers district where he grew up say he keeps to himself. Other acquaintances talk about his obsessive body-building.

"The saliva sample, we have that," says Fleming. But where are the results of the DNA test, conducted on the spit ball over four months ago? "We have not received a DNA report," says Fleming. "The FBI wants a flawless examination of the DNA samples because of some recent controversies involving DNA evidence. If we do make an arrest based on DNA evidence, we want to have the right man."

In the meantime, the police are still searching for more bodies. "We've been through the area again," confirms Fleming, who says it's almost certain the killer has struck more than 24 times. "But we're talking about a Louisiana swamp. A body could stay there quite some time before it's discovered."

If Gant's DNA tests clear his name, the FBI and the NOPD will have spent over $3m on their investigation with no results. "That's not uncommon with these cases," says Fleming. "A smart serial killer can always stay one step ahead, that's why we have so many of them." With more to come, experts fear. Next week the US congress will vote on a bill that will give the FBI serial killer programme an extra $20m in funding. "It's the least we need to contain the problem," says Cooper.

That's all fine but with existing police resources the score in New Orleans is still 24 deaths and no arrests. The only suspect is a police officer who remains at his desk, accessible by telephone.

When we spoke last week, police department badinage was audible in the background. Gant the serial killer suspect listened to my questions about his DNA tests. "I really can't answer that," he said in a Louisiana drawl. "You'll have to call my attorney. Let me give you his number."

I told him I had his attorney's number, but could he answer any questions? "Only if you want to talk about the weather," he said.

I didn't, at least not until he's been cleared of the allegations against him. Until then, he's just one of 60 suspected serial killers in America who could strike again at any time.