Investigations into the killing of Samajwadi Party MP Phoolan Devi continue to be marked by confusion and muckraking.

Even as the four men suspected of gunning her down on July 25 have been arrested, new theories cropping up every day have baffled the police of Delhi, Uttar Pradesh and Uttaranchal.

As the police launched a manhunt for the killers, the key accused, Sher Singh Rana alias Pankaj, gave himself up to the Uttaranchal police on July 27. The police initially said two other gunmen were involved. But on July 30, three days after Rana's surrender, three men were arrested at Saharanpur town in Uttar Pradesh on charges of being party to the crime.

They were identified as Ravinder, Rajbir and Shekhar Singh. Now, a week after the killing, it is being rumoured that one of them may not be a killer after all.

Some officials say Rana and Ravinder were probably in an Uttar Pradesh jail at the time of the murder.

An embarrassed Delhi police admits that Ravinder was not involved in the killing and that it was another man known as Vicky who took part in the crime. Ravinder was arrested because Rana named him an accomplice, they say.

While the police say Ravinder may have been in jail on July 25, they feel that Rana - who they insist is the man who pulled the trigger - is trying to derail police investigations.

"An impostor could have been in the jail. This is a common practice employed by criminals as it provides a credible alibi to say they were not at the murder site," a senior officer says.

"Rana wants to weaken the prosecution case. It seems he planned to reveal during the trial that he was in prison when Phoolan Devi was killed. The jail records would have backed his claim. The court would have been forced to set both free."

"But we believe that while Ravinder may have been in jail, the Sher Singh Rana who was in prison was not the same man who surrendered to the police."

There is more mystery. The police are baffled how two indigenous revolvers, popularly known as kattas, landed at the garage of the slain MP's government bungalow nearly four days after the murder.

Rana said he had thrown away the weapons after shooting Phoolan Devi. Police say a member of her Samajwadi Party, Keshav Pradhan, picked them up, wrapped them in a cloth and kept them at the garage.

Another party activist stumbled on the weapons and tipped off the police. Phoolan Devi's family is giving more headaches to the police.

Munni Devi, Phoolan's sister, has accused the slain MP's husband Umed Singh of the murder. Umed Singh has denied the charge but the police say he is also a suspect.

Then there is speculation about the role played by a woman political activist, Uma Kashyap, who was close to Sher Singh Rana and had introduced him to Phoolan Devi. Kashyap now says she knew nothing about Rana's criminal bent of mind. The police are not totally convinced.