2 Samuel 4

   ¹And when Saul's son heard that Abner was dead in Hebron, his hands were feeble, and all the Israelites were troubled.
   ²And Saul's son had two men that were captains of bands: the name of the one was Baanah, and the name of the other Rechab, the sons of Rimmon a Beerothite, of the children of Benjamin: (for Beeroth also was reckoned to Benjamin.
   ³And the Beerothites fled to Gittaim, and were sojourners there until this day.)
   ⁴And Jonathan, Saul's son, had a son that was lame of his feet. He was five years old when the tidings came of Saul and Jonathan out of Jezreel, and his nurse took him up, and fled: and it came to pass, as she made haste to flee, that he fell, and became lame. And his name was Mephibosheth.

 How does the lame become lame? I suppose he could break his crutch but that sounds too painful for words.

   ⁵And the sons of Rimmon the Beerothite, Rechab and Baanah, went, and came about the heat of the day to the house of Ishbosheth, who lay on a bed at noon.
   ⁶And they came thither into the midst of the house, as though they would have fetched wheat; and they smote him under the fifth rib: and Rechab and Baanah his brother escaped.
   ⁷For when they came into the house, he lay on his bed in his bedchamber, and they smote him, and slew him, and beheaded him, and took his head, and gat them away through the plain all night.

Nothing like a quick getaway then, and that was absolutely nothing like a quick getaway.  Either that, or the slowest known decapitation in history.
 
   ⁸And they brought the head of Ishbosheth unto David to Hebron, and said to the king, Behold the head of Ishbosheth the son of Saul thine enemy, which sought thy life; and the LORD hath avenged my lord the king this day of Saul, and of his seed.
   ⁹And David answered Rechab and Baanah his brother, the sons of Rimmon the Beerothite, and said unto them, As the LORD liveth, who hath redeemed my soul out of all adversity,
   ¹⁰When one told me, saying, Behold, Saul is dead, thinking to have brought good tidings, I took hold of him, and slew him in Ziklag, who thought that I would have given him a reward for his tidings:
   ¹¹How much more, when wicked men have slain a righteous person in his own house upon his bed? shall I not therefore now require his blood of your hand, and take you away from the earth?

Perhaps when David sent word to Ishbosheth that he wanted his wife, Michal returned to him Rechab and Baanah thought David was asking for a little head.
   ¹²And David commanded his young men, and they slew them, and cut off their hands and their feet, and hanged them up over the pool in Hebron. But they took the head of Ishbosheth, and buried it in the sepulchre of Abner in Hebron.