Below is an article published by the Guardian Unlimited newspaper on the inquiry on Anna Politkovskaya murder.

Police officers in a Siberian town are alleged to be obstructing the arrest of a former major on their force who is wanted for questioning in connection with the murder of the Russian journalist Anna Politkovskaya, the Guardian has been told.

Alexander Prilepin, who is also wanted in connection with the torture and disappearance of a young Chechen man in Grozny in 2001, is said to have been spotted in Nizhnevartovsk but loyal officers there are alleged to have helped him escape capture.

One line of inquiry being pursued by prosecutors is that an officer from the Khanty Mansiysk region of Siberia killed her in revenge for publicising the torture case - leading to a trial that saw one of their police colleagues, nicknamed “Cadet”, imprisoned for 11 years. Mr Prilepin was a major on the force.

Politkovskaya, a newspaper reporter and author who brought the Kremlin’s dirty war in Chechnya to an international audience, was shot dead in the lift of her central Moscow apartment block on October 7. President Vladimir Putin has promised a thorough investigation into the murder, which provoked shock and outrage across the world.

Suspicion has fallen on three groups in relation to Politkovskaya’s death: Ramzan Kadyrov, the Chechen prime minister whom she criticised for alleged human rights abuses; an opponent of Mr Kadyrov who wanted to discredit him; or a subject of one of her investigative articles who was incensed about being exposed.

Last week a team of prosecutors, detectives and federal security service agents investigating Politkovskaya’s death was in Nizhnevartovsk, 1,200 miles east of the Russian capital, looking for Mr Prilepin. The team drew a blank after questioning friends and relatives of Mr Prilepin.

However, a Chechen law enforcement source who was recently dispatched to Nizhnevartovsk with a separate group to search for Mr Prilepin told the Guardian: “The police there are pretending to look but in fact they are just helping hide their old comrade, and doing everything they can to stop him being found.

“Prilepin’s first wife and other sources told us he is living there and riding around in a jeep. But the prosecutors from Moscow won’t find anything. The local officers warn him whenever anyone comes near.”

An arrest warrant for Mr Prilepin was announced earlier this year in connection with the torture and disappearance of Zelimkhan Murdalov, a 26-year-old Chechen who was arrested in Grozny in January 2001.

The young man was taken to a detention facility in the city’s Oktyabrsky district. According to witnesses an officer called Sergei Lapin, or Cadet, tried to slice off Murdalov’s ear, beat him and submitted him to electric shocks in an attempt to force him to become an informer. Murdalov disappeared the day after his detention. Mr Prilepin is suspected of helping to dump his body.

The incident went virtually unnoticed until nine months later when Politkovskaya publicised it in an article called “Disappearing People”.

“If it hadn’t been for Anna’s efforts, Lapin would never have been prosecuted,” said Murdalov’s father, Astemir, 55, in an interview at his home in Grozny. “It’s quite possible they killed her in revenge for his imprisonment.”

Lapin, who denied torture and said Murdalov received his injuries falling down some stairs, was convicted last year. Before the trial he sent emails to Politkovskaya demanding she retract the accusations made in her article, “otherwise the police officer hired by you as a guard will not be enough to help you”.

Murdalov’s relatives have been repeatedly threatened. Armed men in masks have broken into the house of Murdalov’s father and searched it on three occasions, once holding an automatic weapon to his head. His mother, Rukiyat, and sister, Zalina, moved to Norway in 2003 in fear for their safety. On one occasion they found a note in their postbox made from letters cut from newspapers, saying “You will answer for Lapin”. Last year an unknown assailant attacked Rukiyat near her home, slashing her neck and wrists with a knife.

Mr Prilepin was not arrested at the time of Lapin’s trial, despite damning evidence given against him by witnesses. Another nine officers from Khanty Mansiysk are now being sought for questioning about abuses at the Oktyabrsky detention centre.