It was a grenade- police chief

 

This is a military weapon, usually thrown at enemy forces during war. The grenade explodes and kills or destroys buildings when thrown from a short distance. It was not immediately clear how the grenade, a strictly military weapon, which is not sold at any shop or warehouse, landed at the Office of the President. The police say they are still investigating. It seems whoever left the grenade did not intend it to explode.

Wikipedia says that a hand grenade is an anti-personnel weapon that explodes a short time after release. However the hand grenade found at the OP did not explode for hours after it was found around 7am. The police say the weapon, described in the press as an explosive device was diffused in the afternoon after security personnel were called to the scene.  Kapinga told Mmegi he would not get into details as to how long it takes for a grenade to explode, as he is not a weapon's expert.

Wikipedia says that for a grenade to cause any harm or destruction, it has to be thrown from a short distance. It is capable of killing people and causing destruction within a five metre radius. Kapinga said a grenade is a small weapon that can be easily concealed and this is why security at the OP failed to detect it before it was 'planted' inthe parking lot. He explained that the OP building is from time to time guarded by government security personnel who do not have military training. Sometimes soldiers from the Botswana Defence Force (BDF) guard the premises.

The head of Directorate on Intelligence and security (DIS) declined to say whether the grenade incident means that Khama's life is in danger.

Meantime Khama arrived yesterday from Australia amidst fears that he could be targeted by those who 'planted' the grenade.  Kgosi would not say whether the president would head straight to his office to work from there. The Minister of Defence and Security, Ramadeluka Seretse said he could not comment because he was outside the country.-