Bombs!?

[surmav 33]

I was trying to escape from 2 bandits, they shot at me, etc.. Finally i made some distance, ran into house, stayed hidden at second floor. Suddenly i heared some foot steps downstairs, I was ready to shoot who ever would come in, no one came.. Suddenly huge explosion happened and i was dead. I had no idea that there are bombs in game till now. My question is, what kind of bombs are in the game and how to make them :)?

[Tactical Nuke 47]

http://dayz.gamepedia.com/Weapons#Grenades

[BadAsh (DayZ) 1513]

And grenade explosions can unfortunately go through walls. So if they know where you were hiding, they can just drop a grenade outside the building next to that room and you are a goner.

[DMentMan 707]

probably a grenade