have blood on (your) hands

to be responsible for someone's death.

The leaders of this war have the blood of many thousands of people on their hands.

• on the front lines of something
• on the heels of
• on the heels of something
• on the hoof
• on the horizon
• on the horns of a dilemma
• on the hour
• on the house
• on the job
• on the lam
• on the level
• on the line
• on the loose
• on the margins of
• on the margins of something
• on the market
• on the mend
• on the merits
• on the money
• on the move
• on the nail
• on the never-never
• on the nod
• on the nose
• on the off-chance