Police in Italy are hunting the relatives of a Pakistani girl who they think was strangled to death and buried in a shallow grave in a so-called honour killing.

Saman Abbas, 18, has been missing since May 1 when she was last seen on CCTV at a farm near the city of Reggio Emilia, central Italy, where father Shabbar, 46, worked.

Police says Shabbar conspired with Saman’s mother Nazia Shaheen, 47, uncle Hasnain Danish, 33, and cousins Nomanulhaq Nomanulahq and Ijaz Ikram, 33 and 28, to kill her and bury her body behind the farm before fleeing the country.

Investigators believe the relatives hatched the plot after Saman refused to enter into an arranged marriage with a cousin in Pakistan because she had a boyfriend in Italy and wanted to live a ‘Western’ lifestyle.

Ijaz has since been arrested in France on suspicion of murder and extradited back to Italy. Shabbar and Nazia are in Pakistan and have denied murder of their daughter.

The whereabouts of Hasnain – who prosecutors say masterminded the killing – and Nomanulhaq are unknown.

Prosecutors say the case dates back to autumn last year, when the family tried to force Saman into an arranged marriage in her native Pakistan.

Saman fled the family home after an argument and since October had been living in a refuge run by social services, fearing for her safety.

But she returned home on April 11 this year, apparently to collect identity documents – though it is unclear exactly why she needed them.

Police believe that by April 26 the family had begun preparing for her murder.

That is the date on which uncle Hasnain is alleged to have bought plane tickets for her parents to fly back to Pakistan, prosecutors say.

Then, on the evening of April 29, CCTV captured three men who police say are Hasnain, Nomanulhaq and Ijaz walking into fields behind the farm around 7.30pm.

The trio are carrying two shovels, a bucket, and a blue bag with a crowbar in it. They are gone for around two hours, before returning home.

The following day, Saman reportedly overheard a conversation between her relatives, and told her boyfriend that they were planning her murder.

Saman’s boyfriend, who was not at the property, told Italian newspaper Gazzetta di Reggio Emiliano that she texted him saying she had overheard her uncle remark that murder is ‘the only solution’ for girls who disobey Pakistan’s strict honour codes.

The boyfriend was instructed to contact police in two days if she hadn’t messaged him.

The boyfriend said he tried to reassure her, but she said: ‘I’m not confident.’

Police say more CCTV footage – which hasn’t been published – then shows parents Shabbar and Nazia walking their daughter into the fields behind the farm at nine minutes past midnight on May 1.

The pair return just 13 minutes later, with father Shabbar carrying a backpack that Saman had previously been wearing.

Police believe the parents handed Saman over to her uncle and cousins who were waiting in the fields and who killed her and buried her body somewhere on the farm.

The family then left home – Shabbas and Nazia for Pakistan, ostensibly to visit a sick relative, while Ijaz headed into Europe.

When police called at the family farm looking for Saman on May 5, they found Hasnain and Saman’s 16-year-old brother at home, who explained that the rest of the family had gone to Pakistan to see a sick relative, Corriere reports.

Then the pair also vanished. On May 9 they were stopped at the Italian border with France because the brother was not carrying his identity documents.

Hasnain was released but the brother was detained. While being interviewed by police, he told them of his suspicions that Hasnain orchestrated his sister’s killing with the help of his relatives.

The boy claims the whole family was afraid of Hasnain, who he believes strangled his sister to death following a row over identity documents.

He claimed to have overheard the argument on the night his sister disappeared, before seeing his father come home in tears followed by his uncle and cousins.

Based on the teenager’s testimony, the police have now issued warrants for the family on suspicion of premeditated murder and concealment of a body.

A phone has since been uncovered which allegedly contains a text sent from Hasnain to a friend which reads simply: ‘Job well done.’ Police say this was a reference to the killing.

Ijaz was then arrested in France on June 6 while boarding a bus bound for Barcelona, where he is thought to have relatives.

He was extradited back to Italy, where he arrived on Wednesday this week. Hasnain and Nomanulhaq are also thought to be somewhere in Europe, but their exact whereabouts are unknown.

Shabbar and Nazia are in Pakistan, and have spoken to Italian journalists to deny the murder of their daughter, who they say is alive an in Belgium. Prosecutors want to have the pair extradited.

Meanwhile searches are still ongoing at the farm to try and find Saman’s body.

Electromagnetic scanners have been brought in along with sniffer dogs to try and detect the remains, while waterways are also being dredged.

‘The search for the remains of the injured person continues, who unfortunately we believe is dead,’ prosecutor Prosecutor Isabella Chiesi told Reppublica.

‘I would not give any positive feedback to what the father said, we have ascertained that the girl is not in Belgium.’

The case has shocked Italy, with the Union of Islamic Communities issuing a religious ruling denouncing forced marriages following Saman’s disappearance.