Officials in Pakistan's largest city Karachi say at least 40 people have been killed in an outburst of communal violence that followed the assassination of a local lawmaker.
Dozens of vehicles and shops were set on fire as security forces struggled to regain control of the city.
It could have been anybody, was the response of one political analyst to the question of who shot down provincial legislator Raza Haider outside a Karachi mosque.
What the analyst, Hasan-Ascari Rizvi, meant was that the killers could have been from any one of the myriad political, criminal, sectarian and ethnic factions that make up the social fabric of Pakistan's teeming commercial capital.
Officials say more than 170 people have died in political killings in Karachi this year, though rights organizations say the toll is much higher.
Pakistani Interior Minister Rehman Malik speaking after the August 2 killing, appealed for the public "not to speculate as to who is behind this murder until we investigated this."
Malik added that he thought the killing was "a new formula to destabilize Pakistan and in particular Karachi, which is the hub of our economic activities. This is an attempt to cripple it."
The superintendent of police in Karachi, Fayaz Khan, told RFE/RL's Radio Mashaal that suspicion falls on a radical group called Fazal Mehsud.
He said the group belonged to the Lashkar-e Jhangvi movement and "was also involved in the attack on the Ahmadis' place of worship in Lahore. Things will be clear in the coming two to three days and maybe the group members will be arrested."
Karachi's Volatile Mix
Haider was a member of the Muttahida Qaumi Movement (MQM), the political party that runs the city and represents mainly descendants of Urdu-speaking Mohajir migrants from India who settled in Pakistan when it was created in 1947.
The MQM's main political rival is the Awami National Party, a secular nationalist party whose main power center is Pakistan's northwest and whose basis in Karachi is the ethnic Pashtun community.
The Associated Press notes that It's long been said that members of all political parties in Karachi are heavily involved in criminal activities such as protection rackets and illegal land dealings.
There is also the drug mafia, and an increasing number of Taliban militants who have moved to the city to avoid the Pakistani Army's drive into their strongholds in the northwest.
Add to this religious and ethnic tensions, and the mix is volatile, with violence never far away. So it proved on August 2, when gunmen took to the streets, killing at least 40 people in the wake of Haider's assassination and injuring about 90.
A spokesman for the Awami National Party, Qadar Khan, told Radio Mashaal that a large number of those killed were Pashtuns.
"Three of our party workers were killed. Then three Pashtun constables and two security guards were also killed yesterday," he said.
"Ten other Pashtun pedestrians, who were on way to their houses, were targeted. Thirteen others who were traveling in buses were attacked."
One of the injured is Akbar Khan, who told Radio Mashaal from his hospital bed that armed men killed two other men in front of him.
"I was praying when unknown people came in and opened fire," he said. "They shot two other people praying in the head and also fired seven rounds at me. God saved me. I received four to five bullets in one hand, and one bullet hit my head."
Buildings were burned down and vehicles destroyed in the rampage, which police had difficulty quelling.
Some scattered shooting could still be heard in the almost-deserted streets today, and some new fires were burning. Schools and shops are closed.
Sindh Province spokesman Jamil Soomro said the provincial government believed -- like Interior Minister Malik -- that the events were the work of "forces who want to destabilize the elected government."
The trouble comes at a bad moment for the Pakistani government, which is overwhelmed by the flood disaster in the northwest.
Businessmen in Karachi are also upset that the riots give a fresh indication of the city's fragile stability at a time when foreign investment is particularly sought. Karachi is the seat of Pakistan's central bank and stock exchange, as well as the country's main port.
with material from RFE/RL's Radio Mashaal and agency reports