This could be a real whodunit, because the underlying murder case is also a bit of a whodunit. Gunmen on motorcycles (or perhaps in a taxi) assassinated the top prosecutor in Pakistan, who had been preparing a case on the assassination of Benazir Bhutto in 2007. CNN points to a number of potential suspects:

The Washington Post looks more specifically at the recently returned Pervez Musharraf, whom Chaudhry Zulfikar had accused of taking part in the Bhutto killing, and who has been under house arrest for a couple of weeks after having his bail revoked:

In an attack that shocked the usually sedate capital, gunmen on Friday morning shot to death the Pakistani government’s top prosecutor in a case accusing former military ruler Pervez Musharraf of involvement in the 2007 assassination of ex-prime minister Benazir Bhutto, police said.

The gunmen, riding in a taxi, sprayed state prosecutor Chaudhry Zulfikar’s car with bullets as he was leaving his home here en route to an anti-terrorism court in nearby Rawalpindi for trial proceedings in the Bhutto case. …

In the one unfolding in Rawalpindi, prosecutors have alleged that Musharraf was culpable for Bhutto’s murder for not providing her enough security. He has denied the allegations.

At the time, Musharraf’s government blamed the Taliban for the fatal attack on Bhutto, a two-time prime minister.

But don’t necessarily lock into one suspect, either.  The Taliban has conducted their usual manner of public engagement of late — killings:

Zulfikar’s death comes amid a spate of political killings by the Pakistani Taliban, which has launched concentrated attacks against secular parties as part of the militants’ avowed efforts to derail the May 11 national election that would bring the first transfer of power between elected governments in Pakistan’s 65-year history.

And as CNN notes, it might be the same group that conducted the Mumbai attack, Lashkar-e-Taiba.  The Pakistani intelligence service ISI has supported LeT in the past (as they have the Taliban), and they may have concerns that Pakistan’s prosecutors might get too interested in bringing these terrorist groups to heel.

In other words, this is a real whodunit, just as much as with Bhutto’s assassination — and it’s unlikely that we’ll ever get answers in either.