YOU know the speed of light, but has this question ever occurred to you: "Okay, what is the speed of dark?" This bizarre issue has been raised by Wright Stevens, a Hollywood movie director. But he may have made a scientific point that could bear a philosophical relevance to a real life situation.

When light cannot penetrate an obstacle, a shadow forms on the other side. That way, light and darkness appear as instantaneous phenomena having equal speed, if you will.

Whilst light is welcomed, shadow is not. The former with the tool of transparency shines the path to solution; the latter is part of the problem and not of solution.

Signaling no material change in the investigative narrative on Cesare Tavella's murder, Home Minister Asaduzzaman Khan Kamal has retracted from a previous statement on BNP leader Quayum. The allegation that 'he was behind the September 28 Italian citizen's murder' has been rephrased into his being 'one of the top suspects'. But the minister later thought he was wrongly quoted by the media on this issue.

The reason behind the change of emphasis apparently resides in the disclosure under the borobhai category: 'Not only Quayum, others are also on the list, according to information available to us', the minister added with a hint of retaining operational flexibility.

Quayum's family has claimed that he had been away from the country in Malaysia for six months, a claim that is clearly verifiable as an extenuating circumstance, other things remaining the same.

The police were obviously under pressure to come out with results in their investigation. The detectives paraded four accused killers, the trigger having been pulled at Travella by Rubel who made a confessional statement in this respect. 

The police are yet to recover the weapon used in the murder, though the ballistic report on the bullet they had found is in the hands of investigators. Criminologists tend to emphasize synchronization between ballistic report on the weapon and that of the bullet which we believe the police would regard as key element in solving the case.

In parallel, Humayun Kabir Hira arrested in connection with the killing of Japanese citizen Kunio Hoshi in Rangpur too made a confessional statement before a senior judicial magistrate on Wednesday. 

Going by a BBC report, Sohel, one of the suspected accused in the Kunio case is hiding in Britain. 

Let's face up to a customary practice of falling in a denial trap as though hesitating to own up to the embarrassment of failing to avert a nefarious design. Even in countries where governance is rated high, the government does not shy away from addressing an untoward incident lest it bring it to a greater disrepute. 

More to the point, no sooner had an investigation begun people in high places started voicing opinions and engaging in name calling. It is no rocket science to grasp that these tend to influence the course of investigation and consequently, its outcome. 

In all, however, we take the position that the investigations are far from being done and dusted. And, that these will continue in earnest to get to the heart of the matter. Keep an open mind to plausible options so that when the prosecution is prepared it is foolproof, credible and unassailable by standard legal yardsticks. 

SITE Intelligence Group, stands by its reports on IS claims to both the foreigners' killings as well as the Hossaini Dalan grenade attack on the eve of Ashura, linking the latter to 'soldiers of Khalifa'. The for-profit organisation, understandably finicky about its reliability, asserted that the claims have been authenticated and found credible by its 'rigorous verification process'. 

The home minister is equally assertive debunking the claims saying that these were not uploaded on IS' official website. Meanwhile, the US State Department spokesperson has said that US was not 'certain' about the presence of Islamic State (IS) in Bangladesh. 

Such debates are like dancing around semantics and nomenclatures. The operative words are extremism and terrorism; so what's in a name, terrorism is terrorism. The threats have always been there and to be fair to ourselves some of the major terrorist acts have not seen handing out of convictions to the perpetrators.

Let us not even unwittingly convey a sense that we are stuck with a set piece narrative, whatever its apparent merit to the exclusion of other possibilities. Disgruntled elements are there and who knows what façade they may be using to hide behind as they carry out their lethal agenda. 

To end on a Wright Steven's quote again, 'The severity of the itch is proportional to the reach.'

The writer is Associate Editor, The Daily Star.