THE police in Karachi say they still have an open mind about the murder, late on May 18th, of Zohra Shahid Hussain, a senior politician with the opposition Pakistan Tehreek-e-Insaf (PTI), or Movement for Justice. The three young men on a motorcycle who attacked her outside her home may have been robbers, they say. Her party colleagues, however, are in no doubt that she fell victim to a political assassination. She died on the eve of a partial rerun in one Karachi constituency of the general election held on May 11th. PTI’s leader, Imran Khan, a charismatic former captain of the national cricket team, was quick to blame Altaf Hussain, the exiled leader of Karachi’s dominant political party, the Muttahida Qaumi Mahaz, or MQM, as “directly responsible” for the murder. The MQM was equally quick to deny the charge, accusing Mr Khan of “immaturity” and threatening to sue him for defamation.

Karachi has a terrible record of violence, much of it political. Eleven people were killed on May 18th alone. Political parties have close links to gangsters, and the city is also home to extremists from the Pakistani Taliban and other groups with terrorist tendencies. The MQM is both the best-organised of the city’s political parties, and, as the one in power, seen as the best able to bully and intimidate its rivals. “It is a fascist party,” says Arif Alvi, the PTI’s candidate in the contested constituency.

Against this background, Mr Khan accused Mr Hussain of openly threatening PTI workers through public broadcasts. Police in Britain are investigating Mr Hussain after receiving hundreds of complaints about a speech he made on May 12th, which the PTI took to be inciting violence against its workers. The MQM insists its leader’s words were taken out of context and misinterpreted.

On the ground in Karachi, Mr Alvi is also convinced his colleague was killed by political rivals. She died of two bullets through the head, shot from under the chin. He says that, overnight, the noise of guns fired into the air could be heard through much of the constituency. He likens this to an MQM tactic used in advance of the strikes it sometimes calls—violence the previous evening intimidates people into observing its orders.

In one part of the constituency, Hijrat Colony, an area of tumbledown shacks and cramped breeze-block houses, residents say men on motorcycles had driven round on the eve of the poll, telling people not to vote in the morning. The MQM boycotted the re-poll, demanding fresh voting in all of the constituency's polling stations, not just the 43 designated by the Election Commission (EC), after allegations of vote-rigging and of EC incompetence in failing to provide the polling stations with ballot papers and voters’ lists.

The boycott was also observed by the Pakistan Peoples Party (PPP), which, despite being trounced in the national election, remains the main party in the province of Sindh of which Karachi is part; and by Jamaat-e-Islami, an Islamic party which was contesting it under a seat-sharing arrangement with the Pakistan Muslim League (N), the PML-N, which triumphed nationally.

The MQM has dominated politics in Karachi for three decades. It was formed to represent the interests of the Mohajirs—Urdu-speaking migrants who came to the city after partition from India in 1947. The city has expanded enormously—to a population of an estimated 18m today. The MQM has maintained its supremacy despite challenges from the PPP, which represents mainly the Sindhis, and the Awami National Party (ANP), representing the many ethnic Pushtuns who have moved to the city in recent years.

But on May 11th, the PTI emerged as the main opposition, the runner-up in 15 of 17 seats declared. Some of this was achieved by mobilising the so-called “burger class”, the well-educated elite that has hitherto tended to shun politics, and is now, nationwide, a leading force in what Mr Khan calls a “tsunami” started by the PTI. In a posh school used as a polling station in Karachi’s Defence Housing Authority, many well-dressed middle-aged residents were voting for the first time.

In Hijrat and elsewhere, however, the PTI is clearly also eating into the MQM’s support. Overall the MQM's share of the vote in Karachi on May 11th fell from 72% in the previous election in 2008 to 61% now. If the MQM did intend to intimidate voters ahead of the voting, it seems to have some success. Most polling stations reported low turnout, and PTI voters (the only ones to be found) said that others had been scared to come, despite the heavy presence of soldiers, policemen and paramilitary rangers at all the polling stations.

In the nation's capital, Islamabad, officials and foreign diplomats alike see the election on May 11th as having been the most successful, in terms of the credibility of the process, in Pakistan’s history. The result, giving the PML-N the chance to lead a strong central government, has also been welcomed. And the PTI’s surge—coming from nowhere to challenge the PPP as the main national opposition—has been seen as a big factor in the high turnout in most parts of the country.

Karachi, however, presents the incoming government with one of its biggest problems. The MQM, an influential player in most previous federal coalitions, is now out of government in Islamabad, and facing what Mr Alvi says is the biggest challenge left to its dominance of Karachi. It still, however, has its coercive power, and the fanatical loyalty Mr Hussain commands among many of the MQM’s foot-soldiers.

It also has the power to embarrass Britain, for Mr Hussain is a British citizen. Mr Khan has already said he also holds the British government responsible for Ms Hussain’s murder.

(Picture credit: AFP)