He slept with a married woman.

He slept with a married woman.  When he heard that she was pregnant,

he tried to cover it up by making her husband to go down to his house twice

so that the husband could sleep with his wife and her pregnant baby was the couple’s and not his own. 

He even made him drunk and tried to make her husband to go down to his house

so that the husband could sleep with her.  But the plan failed.

Eventually, he even planned to kill the husband and actually killed him.

He did evil in the sight of God. (2 Sam. 11:5-27)