What two reasons did the British have for marching on Lexington and concord

1) The British heard that the two patriot leaders, John Hancock and Samuel Adams were in Lexington. They needed to go to Lexington to capture the two leaders.

2) The British heard that the Americans were hiding weapons. The British soldiers were sent to Lexington to retrieve the weapons/gunpowder.

Capturing rebel leaders and finding stopped off ammunition.